File xapian-core-1.4.21-std-fixes.patch of Package mingw32-xapian-core

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File xapian-core-1.4.21-std-fixes.patch of Package mingw32-xapian-core (Revision d711f460150d0eaec24247edfa2d3d43)

Currently displaying revision d711f460150d0eaec24247edfa2d3d43 , Show latest

diff -ur xapian-core-1.4.21/api/compactor.cc xapian-core-1.4.21/api/compactor.cc
--- xapian-core-1.4.21/api/compactor.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/compactor.cc	2022-11-08 16:44:15.468461543 +0100
@@ -65,11 +65,11 @@
 using namespace std;
 
 class CmpByFirstUsed {
-    const vector<pair<Xapian::docid, Xapian::docid>>& used_ranges;
+    const std::vector<pair<Xapian::docid, Xapian::docid>>& used_ranges;
 
   public:
     explicit
-    CmpByFirstUsed(const vector<pair<Xapian::docid, Xapian::docid>>& ur)
+    CmpByFirstUsed(const std::vector<pair<Xapian::docid, Xapian::docid>>& ur)
 	: used_ranges(ur) { }
 
     bool operator()(size_t a, size_t b) const {
@@ -82,11 +82,11 @@
 class Compactor::Internal : public Xapian::Internal::intrusive_base {
     friend class Compactor;
 
-    string destdir_compat;
+    std::string destdir_compat;
     size_t block_size;
     unsigned flags;
 
-    vector<string> srcdirs_compat;
+    std::vector<string> srcdirs_compat;
 
   public:
     Internal() : block_size(8192), flags(FULL) { }
@@ -109,13 +109,13 @@
 }
 
 void
-Compactor::set_destdir(const string & destdir)
+Compactor::set_destdir(const std::string & destdir)
 {
     internal->destdir_compat = destdir;
 }
 
 void
-Compactor::add_source(const string & srcdir)
+Compactor::add_source(const std::string & srcdir)
 {
     internal->srcdirs_compat.push_back(srcdir);
 }
@@ -132,14 +132,14 @@
 }
 
 void
-Compactor::set_status(const string & table, const string & status)
+Compactor::set_status(const std::string & table, const std::string & status)
 {
     (void)table;
     (void)status;
 }
 
 string
-Compactor::resolve_duplicate_metadata(const string & key,
+Compactor::resolve_duplicate_metadata(const std::string & key,
 				      size_t num_tags, const std::string tags[])
 {
     (void)key;
@@ -152,15 +152,15 @@
 XAPIAN_NORETURN(
     static void
     backend_mismatch(const Xapian::Database & db, int backend1,
-		     const string &dbpath2, int backend2)
+		     const std::string &dbpath2, int backend2)
 );
 static void
 backend_mismatch(const Xapian::Database & db, int backend1,
-		 const string &dbpath2, int backend2)
+		 const std::string &dbpath2, int backend2)
 {
-    string dbpath1;
+    std::string dbpath1;
     db.internal[0]->get_backend_info(&dbpath1);
-    string msg = "All databases must be the same type ('";
+    std::string msg = "All databases must be the same type ('";
     msg += dbpath1;
     msg += "' is ";
     msg += backend_name(backend1);
@@ -175,7 +175,7 @@
 namespace Xapian {
 
 void
-Database::compact_(const string * output_ptr, int fd, unsigned flags,
+Database::compact_(const std::string * output_ptr, int fd, unsigned flags,
 		   int block_size,
 		   Xapian::Compactor * compactor) const
 {
@@ -184,7 +184,7 @@
     bool renumber = !(flags & DBCOMPACT_NO_RENUMBER);
 
     enum { STUB_NO, STUB_FILE, STUB_DIR } compact_to_stub = STUB_NO;
-    string destdir;
+    std::string destdir;
     if (output_ptr) {
 	// We need a modifiable destdir in this function.
 	destdir = *output_ptr;
@@ -204,7 +204,7 @@
 
     int backend = BACKEND_UNKNOWN;
     for (const auto& it : internal) {
-	string srcdir;
+	std::string srcdir;
 	int type = it->get_backend_info(&srcdir);
 	// Check destdir isn't the same as any source directory, unless it
 	// is a stub database or we're compacting to an fd.
@@ -226,9 +226,9 @@
     Xapian::docid tot_off = 0;
     Xapian::docid last_docid = 0;
 
-    vector<Xapian::docid> offset;
-    vector<pair<Xapian::docid, Xapian::docid> > used_ranges;
-    vector<Xapian::Database::Internal *> internals;
+    std::vector<Xapian::docid> offset;
+    std::vector<pair<Xapian::docid, Xapian::docid> > used_ranges;
+    std::vector<Xapian::Database::Internal *> internals;
     offset.reserve(internal.size());
     used_ranges.reserve(internal.size());
     internals.reserve(internal.size());
@@ -308,14 +308,14 @@
 	    internals_.push_back(internals[n]);
 	    used_ranges_.push_back(used_ranges[n]);
 
-	    const pair<Xapian::docid, Xapian::docid> p = used_ranges[n];
+	    const std::pair<Xapian::docid, Xapian::docid> p = used_ranges[n];
 	    // Skip empty databases.
 	    if (p.first == 0 && p.second == 0)
 		continue;
 	    // Check for overlap with the previous database's range.
 	    if (p.first <= last_end) {
-		string tmp;
-		string msg = "when merging databases, --no-renumber is only currently supported if the databases have disjoint ranges of used document ids: ";
+		std::string tmp;
+		std::string msg = "when merging databases, --no-renumber is only currently supported if the databases have disjoint ranges of used document ids: ";
 		internals_[j - 1]->get_backend_info(&tmp);
 		msg += tmp;
 		msg += " has range ";
@@ -339,7 +339,7 @@
 	swap(used_ranges, used_ranges_);
     }
 
-    string stub_file;
+    std::string stub_file;
     if (compact_to_stub) {
 	stub_file = destdir;
 	if (compact_to_stub == STUB_DIR) {
@@ -356,7 +356,7 @@
 	    if (mkdir(destdir.c_str(), 0755) == 0)
 		break;
 	    if (errno != EEXIST) {
-		string msg = destdir;
+		std::string msg = destdir;
 		msg += ": mkdir failed";
 		throw Xapian::DatabaseError(msg, errno);
 	    }
@@ -369,7 +369,7 @@
 	    // that name.
 	    int mkdir_errno = errno;
 	    if (mkdir_errno != EEXIST || !dir_exists(destdir)) {
-		string msg = destdir;
+		std::string msg = destdir;
 		msg += ": cannot create directory";
 		throw Xapian::DatabaseError(msg, mkdir_errno);
 	    }
@@ -417,7 +417,7 @@
     }
 
     if (compact_to_stub) {
-	string new_stub_file = destdir;
+	std::string new_stub_file = destdir;
 	new_stub_file += "/new_stub.tmp";
 	{
 	    ofstream new_stub(new_stub_file.c_str());
@@ -425,7 +425,7 @@
 	    new_stub << "auto " << destdir.substr(slash + 1) << '\n';
 	}
 	if (!io_tmp_rename(new_stub_file, stub_file)) {
-	    string msg = "Cannot rename '";
+	    std::string msg = "Cannot rename '";
 	    msg += new_stub_file;
 	    msg += "' to '";
 	    msg += stub_file;
diff -ur xapian-core-1.4.21/api/documentterm.h xapian-core-1.4.21/api/documentterm.h
--- xapian-core-1.4.21/api/documentterm.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/documentterm.h	2022-11-08 16:44:01.016512919 +0100
@@ -31,7 +31,8 @@
 
 #include <xapian/types.h>
 
-using namespace std;
+using std::string;
+using std::vector;
 
 /// A term in a document.
 class OmDocumentTerm {
@@ -73,7 +74,7 @@
     /** Merge sorted ranges before and after @a split. */
     void merge() const;
 
-    typedef vector<Xapian::termpos> term_positions;
+    typedef std::vector<Xapian::termpos> term_positions;
 
   private:
     /** Positional information.
@@ -182,8 +183,8 @@
      */
     bool is_deleted() const { return positions.empty() && split > 0; }
 
-    /// Return a string describing this object.
-    string get_description() const;
+    /// Return a std::string describing this object.
+    std::string get_description() const;
 };
 
 #endif // OM_HGUARD_DOCUMENTTERM_H
diff -ur xapian-core-1.4.21/api/documentvaluelist.cc xapian-core-1.4.21/api/documentvaluelist.cc
--- xapian-core-1.4.21/api/documentvaluelist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/documentvaluelist.cc	2022-11-08 16:44:15.452461600 +0100
@@ -76,7 +76,7 @@
 string
 DocumentValueList::get_description() const
 {
-    string desc = "DocumentValueList(";
+    std::string desc = "DocumentValueList(";
     if (!at_end()) {
 	desc += "slot=";
 	desc += str(get_valueno());
diff -ur xapian-core-1.4.21/api/error.cc xapian-core-1.4.21/api/error.cc
--- xapian-core-1.4.21/api/error.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/error.cc	2022-11-08 16:44:15.476461514 +0100
@@ -92,7 +92,7 @@
 string
 Xapian::Error::get_description() const
 {
-    string desc(get_type());
+    std::string desc(get_type());
     desc += ": ";
     desc += msg;
     if (!context.empty()) {
diff -ur xapian-core-1.4.21/api/expanddecider.cc xapian-core-1.4.21/api/expanddecider.cc
--- xapian-core-1.4.21/api/expanddecider.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/expanddecider.cc	2022-11-08 16:44:15.464461558 +0100
@@ -30,13 +30,13 @@
 ExpandDecider::~ExpandDecider() { }
 
 bool
-ExpandDeciderAnd::operator()(const string &term) const
+ExpandDeciderAnd::operator()(const std::string &term) const
 {
     return (*first)(term) && (*second)(term);
 }
 
 bool
-ExpandDeciderFilterTerms::operator()(const string &term) const
+ExpandDeciderFilterTerms::operator()(const std::string &term) const
 {
     /* Some older compilers (such as Sun's CC) return an iterator from find()
      * and a const_iterator from end() in this situation, and then can't
@@ -47,7 +47,7 @@
 }
 
 bool
-ExpandDeciderFilterPrefix::operator()(const string &term) const
+ExpandDeciderFilterPrefix::operator()(const std::string &term) const
 {
     return startswith(term, prefix);
 }
diff -ur xapian-core-1.4.21/api/keymaker.cc xapian-core-1.4.21/api/keymaker.cc
--- xapian-core-1.4.21/api/keymaker.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/keymaker.cc	2022-11-08 16:44:15.448461615 +0100
@@ -37,7 +37,7 @@
 string
 MultiValueKeyMaker::operator()(const Xapian::Document & doc) const
 {
-    string result;
+    std::string result;
 
     auto i = slots.begin();
     // Don't crash if slots is empty.
@@ -49,7 +49,7 @@
 	// be adjusted.
 	//
 	// FIXME: allow Xapian::BAD_VALUENO to mean "relevance?"
-	string v = doc.get_value(i->slot);
+	std::string v = doc.get_value(i->slot);
 	bool reverse_sort = i->reverse;
 
 	if (v.empty()) {
diff -ur xapian-core-1.4.21/api/leafpostlist.cc xapian-core-1.4.21/api/leafpostlist.cc
--- xapian-core-1.4.21/api/leafpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/leafpostlist.cc	2022-11-08 16:44:15.476461514 +0100
@@ -101,7 +101,7 @@
 			 stats.rset_size,
 			 stats.total_length));
     }
-    map<string, TermFreqs>::const_iterator i = stats.termfreqs.find(term);
+    std::map<string, TermFreqs>::const_iterator i = stats.termfreqs.find(term);
     Assert(i != stats.termfreqs.end());
     RETURN(i->second);
 }
diff -ur xapian-core-1.4.21/api/maptermlist.h xapian-core-1.4.21/api/maptermlist.h
--- xapian-core-1.4.21/api/maptermlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/maptermlist.h	2022-11-08 16:44:01.012512934 +0100
@@ -30,7 +30,7 @@
 
 #include "omassert.h"
 
-using namespace std;
+using std::string;
 
 class MapTermList : public TermList {
     private:
@@ -52,7 +52,7 @@
 	}
 
 	// Gets current termname
-	string get_termname() const {
+	std::string get_termname() const {
 	    Assert(started);
 	    Assert(!at_end());
 	    return it->first;
diff -ur xapian-core-1.4.21/api/matchspy.cc xapian-core-1.4.21/api/matchspy.cc
--- xapian-core-1.4.21/api/matchspy.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/matchspy.cc	2022-11-08 16:44:15.472461529 +0100
@@ -66,7 +66,7 @@
 }
 
 MatchSpy *
-MatchSpy::unserialise(const string &, const Registry &) const {
+MatchSpy::unserialise(const std::string &, const Registry &) const {
     throw UnimplementedError("MatchSpy not suitable for use with remote searches - unserialise() method unimplemented");
 }
 
@@ -76,7 +76,7 @@
 }
 
 void
-MatchSpy::merge_results(const string &) {
+MatchSpy::merge_results(const std::string &) {
     throw UnimplementedError("MatchSpy not suitable for use with remote searches - merge_results() method unimplemented");
 }
 
@@ -93,7 +93,7 @@
 /// A termlist iterator over the contents of a ValueCountMatchSpy
 class ValueCountTermList final : public TermList {
   private:
-    map<string, Xapian::doccount>::const_iterator it;
+    std::map<string, Xapian::doccount>::const_iterator it;
     bool started;
     intrusive_ptr<Xapian::ValueCountMatchSpy::Internal> spy;
   public:
@@ -105,7 +105,7 @@
 	started = false;
     }
 
-    string get_termname() const {
+    std::string get_termname() const {
 	Assert(started);
 	Assert(!at_end());
 	return it->first;
@@ -127,7 +127,7 @@
 	return NULL;
     }
 
-    TermList * skip_to(const string & term) {
+    TermList * skip_to(const std::string & term) {
 	while (it != spy->values.end() && it->first < term) {
 	    ++it;
 	}
@@ -149,7 +149,7 @@
     Xapian::termcount positionlist_count() const { unsupported_method(); return 0; }
 };
 
-/** A string with a corresponding frequency.
+/** A std::string with a corresponding frequency.
  */
 class StringAndFrequency {
     std::string str;
@@ -189,10 +189,10 @@
 /// A termlist iterator over a vector of StringAndFrequency objects.
 class StringAndFreqTermList final : public TermList {
   private:
-    vector<StringAndFrequency>::const_iterator it;
+    std::vector<StringAndFrequency>::const_iterator it;
     bool started;
   public:
-    vector<StringAndFrequency> values;
+    std::vector<StringAndFrequency> values;
 
     /** init should be called after the values have been set, but before
      *  iteration begins.
@@ -202,7 +202,7 @@
 	started = false;
     }
 
-    string get_termname() const {
+    std::string get_termname() const {
 	Assert(started);
 	Assert(!at_end());
 	return it->get_string();
@@ -224,7 +224,7 @@
 	return NULL;
     }
 
-    TermList * skip_to(const string & term) {
+    TermList * skip_to(const std::string & term) {
 	while (it != values.end() && it->get_string() < term) {
 	    ++it;
 	}
@@ -246,7 +246,7 @@
     Xapian::termcount positionlist_count() const { unsupported_method(); return 0; }
 };
 
-/** Get the most frequent items from a map from string to frequency.
+/** Get the most frequent items from a map from std::string to frequency.
  *
  *  This takes input such as that in ValueCountMatchSpy::Internal::values and
  *  returns a vector of the most frequent items in the input.
@@ -256,14 +256,14 @@
  *                the same frequency will be sorted in ascending
  *                alphabetical order.
  *
- *  @param items The map from string to frequency, from which the most
+ *  @param items The map from std::string to frequency, from which the most
  *               frequent items will be selected.
  *
  *  @param maxitems The maximum number of items to return.
  */
 static void
 get_most_frequent_items(vector<StringAndFrequency> & result,
-			const map<string, doccount> & items,
+			const std::map<string, doccount> & items,
 			size_t maxitems)
 {
     result.clear();
@@ -271,7 +271,7 @@
     StringAndFreqCmpByFreq cmpfn;
     bool is_heap(false);
 
-    for (map<string, doccount>::const_iterator i = items.begin();
+    for (std::map<string, doccount>::const_iterator i = items.begin();
 	 i != items.end(); ++i) {
 	Assert(result.size() <= maxitems);
 	result.push_back(StringAndFrequency(i->first, i->second));
@@ -301,7 +301,7 @@
 ValueCountMatchSpy::operator()(const Document &doc, double) {
     Assert(internal.get());
     ++(internal->total);
-    string val(doc.get_value(internal->slot));
+    std::string val(doc.get_value(internal->slot));
     if (!val.empty()) ++(internal->values[val]);
 }
 
@@ -336,13 +336,13 @@
 string
 ValueCountMatchSpy::serialise() const {
     Assert(internal.get());
-    string result;
+    std::string result;
     result += encode_length(internal->slot);
     return result;
 }
 
 MatchSpy *
-ValueCountMatchSpy::unserialise(const string & s, const Registry &) const
+ValueCountMatchSpy::unserialise(const std::string & s, const Registry &) const
 {
     const char * p = s.data();
     const char * end = p + s.size();
@@ -360,10 +360,10 @@
 ValueCountMatchSpy::serialise_results() const {
     LOGCALL(REMOTE, string, "ValueCountMatchSpy::serialise_results", NO_ARGS);
     Assert(internal.get());
-    string result;
+    std::string result;
     result += encode_length(internal->total);
     result += encode_length(internal->values.size());
-    for (map<string, doccount>::const_iterator i = internal->values.begin();
+    for (std::map<string, doccount>::const_iterator i = internal->values.begin();
 	 i != internal->values.end(); ++i) {
 	result += encode_length(i->first.size());
 	result += i->first;
@@ -373,7 +373,7 @@
 }
 
 void
-ValueCountMatchSpy::merge_results(const string & s) {
+ValueCountMatchSpy::merge_results(const std::string & s) {
     LOGCALL_VOID(REMOTE, "ValueCountMatchSpy::merge_results", s);
     Assert(internal.get());
     const char * p = s.data();
@@ -383,12 +383,12 @@
     decode_length(&p, end, n);
     internal->total += n;
 
-    map<string, doccount>::size_type items;
+    std::map<string, doccount>::size_type items;
     decode_length(&p, end, items);
     while (items != 0) {
 	size_t vallen;
 	decode_length_and_check(&p, end, vallen);
-	string val(p, vallen);
+	std::string val(p, vallen);
 	p += vallen;
 	doccount freq;
 	decode_length(&p, end, freq);
@@ -403,7 +403,7 @@
 
 string
 ValueCountMatchSpy::get_description() const {
-    string d = "ValueCountMatchSpy(";
+    std::string d = "ValueCountMatchSpy(";
     if (internal.get()) {
 	d += str(internal->total);
 	d += " docs seen, looking in ";
diff -ur xapian-core-1.4.21/api/omdatabase.cc xapian-core-1.4.21/api/omdatabase.cc
--- xapian-core-1.4.21/api/omdatabase.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/omdatabase.cc	2022-11-08 16:44:15.464461558 +0100
@@ -126,7 +126,7 @@
 {
     LOGCALL(API, bool, "Database::reopen", NO_ARGS);
     bool maybe_changed = false;
-    vector<intrusive_ptr<Database::Internal> >::iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	if ((*i)->reopen())
 	    maybe_changed = true;
@@ -138,7 +138,7 @@
 Database::close()
 {
     LOGCALL_VOID(API, "Database::close", NO_ARGS);
-    vector<intrusive_ptr<Database::Internal> >::iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	(*i)->close();
     }
@@ -152,14 +152,14 @@
 	LOGLINE(API, "Database added to itself");
 	throw Xapian::InvalidArgumentError("Can't add a Database to itself");
     }
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = database.internal.begin(); i != database.internal.end(); ++i) {
 	internal.push_back(*i);
     }
 }
 
 PostingIterator
-Database::postlist_begin(const string &tname) const
+Database::postlist_begin(const std::string &tname) const
 {
     LOGCALL(API, PostingIterator, "Database::postlist_begin", tname);
 
@@ -174,7 +174,7 @@
     if (rare(internal.empty()))
 	RETURN(PostingIterator());
 
-    vector<LeafPostList *> pls;
+    std::vector<LeafPostList *> pls;
     try {
 	vector<intrusive_ptr<Database::Internal> >::const_iterator i;
 	for (i = internal.begin(); i != internal.end(); ++i) {
@@ -239,7 +239,7 @@
 {
     LOGCALL(API, bool, "Database::has_positions", NO_ARGS);
     // If any sub-database has positions, the combined database does.
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	if ((*i)->has_positions()) RETURN(true);
     }
@@ -247,7 +247,7 @@
 }
 
 PositionIterator
-Database::positionlist_begin(Xapian::docid did, const string &tname) const
+Database::positionlist_begin(Xapian::docid did, const std::string &tname) const
 {
     LOGCALL(API, PositionIterator, "Database::positionlist_begin", did | tname);
     if (tname.empty())
@@ -268,7 +268,7 @@
 {
     LOGCALL(API, Xapian::doccount, "Database::get_doccount", NO_ARGS);
     Xapian::doccount docs = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	docs += (*i)->get_doccount();
     }
@@ -296,7 +296,7 @@
     Xapian::doccount docs = 0;
     Xapian::totallength totlen = 0;
 
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	docs += (*i)->get_doccount();
 	totlen += (*i)->get_total_length();
@@ -320,13 +320,13 @@
 }
 
 Xapian::doccount
-Database::get_termfreq(const string & tname) const
+Database::get_termfreq(const std::string & tname) const
 {
     LOGCALL(API, Xapian::doccount, "Database::get_termfreq", tname);
     if (tname.empty()) RETURN(get_doccount());
 
     Xapian::doccount tf = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	Xapian::doccount sub_tf;
 	(*i)->get_freqs(tname, &sub_tf, NULL);
@@ -336,13 +336,13 @@
 }
 
 Xapian::termcount
-Database::get_collection_freq(const string & tname) const
+Database::get_collection_freq(const std::string & tname) const
 {
     LOGCALL(API, Xapian::termcount, "Database::get_collection_freq", tname);
     if (tname.empty()) RETURN(get_doccount());
 
     Xapian::termcount cf = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	Xapian::termcount sub_cf;
 	(*i)->get_freqs(tname, NULL, &sub_cf);
@@ -357,7 +357,7 @@
     LOGCALL(API, Xapian::doccount, "Database::get_value_freq", slot);
 
     Xapian::doccount vf = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	vf += (*i)->get_value_freq(slot);
     }
@@ -371,9 +371,9 @@
 
     if (rare(internal.empty())) RETURN(string());
 
-    string full_lb;
+    std::string full_lb;
     for (auto&& subdb : internal) {
-	string lb = subdb->get_value_lower_bound(slot);
+	std::string lb = subdb->get_value_lower_bound(slot);
 	if (lb.empty())
 	    continue;
 	if (full_lb.empty() || lb < full_lb)
@@ -388,7 +388,7 @@
     LOGCALL(API, std::string, "Database::get_value_upper_bound", slot);
 
     std::string full_ub;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	std::string ub = (*i)->get_value_upper_bound(slot);
 	if (ub > full_ub)
@@ -405,7 +405,7 @@
     if (rare(internal.empty())) RETURN(0);
 
     Xapian::termcount full_lb = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	// Skip sub-databases which are empty or only contain documents with
 	// doclen==0.
@@ -423,7 +423,7 @@
     LOGCALL(API, Xapian::termcount, "Database::get_doclength_upper_bound", NO_ARGS);
 
     Xapian::termcount full_ub = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	Xapian::termcount ub = (*i)->get_doclength_upper_bound();
 	if (ub > full_ub) full_ub = ub;
@@ -432,13 +432,13 @@
 }
 
 Xapian::termcount
-Database::get_wdf_upper_bound(const string & term) const
+Database::get_wdf_upper_bound(const std::string & term) const
 {
     LOGCALL(API, Xapian::termcount, "Database::get_wdf_upper_bound", term);
     if (term.empty()) RETURN(0);
 
     Xapian::termcount full_ub = 0;
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	Xapian::termcount ub = (*i)->get_wdf_upper_bound(term);
 	if (ub > full_ub) full_ub = ub;
@@ -521,13 +521,13 @@
 }
 
 bool
-Database::term_exists(const string & tname) const
+Database::term_exists(const std::string & tname) const
 {
     LOGCALL(API, bool, "Database::term_exists", tname);
     if (tname.empty()) {
 	RETURN(get_doccount() != 0);
     }
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	if ((*i)->term_exists(tname)) RETURN(true);
     }
@@ -538,7 +538,7 @@
 Database::keep_alive()
 {
     LOGCALL_VOID(API, "Database::keep_alive", NO_ARGS);
-    vector<intrusive_ptr<Database::Internal> >::const_iterator i;
+    std::vector<intrusive_ptr<Database::Internal> >::const_iterator i;
     for (i = internal.begin(); i != internal.end(); ++i) {
 	(*i)->keep_alive();
     }
@@ -564,11 +564,11 @@
 #define VEC_SIZE 64
 
 static int
-freq_edit_lower_bound(const vector<unsigned> & a, const vector<unsigned> & b)
+freq_edit_lower_bound(const std::vector<unsigned> & a, const std::vector<unsigned> & b)
 {
     int vec[VEC_SIZE];
     memset(vec, 0, sizeof(vec));
-    vector<unsigned>::const_iterator i;
+    std::vector<unsigned>::const_iterator i;
     for (i = a.begin(); i != a.end(); ++i) {
 	++vec[(*i) % VEC_SIZE];
     }
@@ -591,7 +591,7 @@
 #define TRIGRAM_SCORE_THRESHOLD 2
 
 string
-Database::get_spelling_suggestion(const string &word,
+Database::get_spelling_suggestion(const std::string &word,
 				  unsigned max_edit_distance) const
 {
     LOGCALL(API, string, "Database::get_spelling_suggestion", word | max_edit_distance);
@@ -616,12 +616,12 @@
     // Convert word to UTF-32.
     // Extra brackets needed to avoid this being misparsed as a function
     // prototype.
-    vector<unsigned> utf32_word((Utf8Iterator(word)), Utf8Iterator());
+    std::vector<unsigned> utf32_word((Utf8Iterator(word)), Utf8Iterator());
 
-    vector<unsigned> utf32_term;
+    std::vector<unsigned> utf32_term;
 
     Xapian::termcount best = 1;
-    string result;
+    std::string result;
     int edist_best = max_edit_distance;
     Xapian::doccount freq_best = 0;
     Xapian::doccount freq_exact = 0;
@@ -631,7 +631,7 @@
 
 	if (merger->at_end()) break;
 
-	string term = merger->get_termname();
+	std::string term = merger->get_termname();
 	Xapian::termcount score = merger->get_wdf();
 
 	LOGLINE(SPELLING, "Term \"" << term << "\" ngram score " << score);
@@ -755,7 +755,7 @@
 }
 
 string
-Database::get_metadata(const string & key) const
+Database::get_metadata(const std::string & key) const
 {
     LOGCALL(API, string, "Database::get_metadata", key);
     if (rare(key.empty()))
@@ -776,9 +776,9 @@
 Database::get_uuid() const
 {
     LOGCALL(API, std::string, "Database::get_uuid", NO_ARGS);
-    string uuid;
+    std::string uuid;
     for (size_t i = 0; i < internal.size(); ++i) {
-	string sub_uuid = internal[i]->get_uuid();
+	std::string sub_uuid = internal[i]->get_uuid();
 	// If any of the sub-databases have no uuid, we can't make a uuid for
 	// the combined database.
 	if (sub_uuid.empty())
@@ -1061,7 +1061,7 @@
 }
 
 void
-WritableDatabase::set_metadata(const string & key, const string & value)
+WritableDatabase::set_metadata(const std::string & key, const std::string & value)
 {
     LOGCALL_VOID(API, "WritableDatabase::set_metadata", key | value);
     if (rare(key.empty()))
diff -ur xapian-core-1.4.21/api/omdocument.cc xapian-core-1.4.21/api/omdocument.cc
--- xapian-core-1.4.21/api/omdocument.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/omdocument.cc	2022-11-08 16:44:15.452461600 +0100
@@ -75,7 +75,7 @@
 }
 
 void
-Document::set_data(const string &data)
+Document::set_data(const std::string &data)
 {
     LOGCALL_VOID(API, "Document::set_data", data);
     internal->set_data(data);
@@ -104,7 +104,7 @@
 }
 
 void
-Document::add_value(Xapian::valueno slot, const string &value)
+Document::add_value(Xapian::valueno slot, const std::string &value)
 {
     LOGCALL_VOID(API, "Document::add_value", slot | value);
     internal->add_value(slot, value);
@@ -125,7 +125,7 @@
 }
 
 void
-Document::add_posting(const string & tname,
+Document::add_posting(const std::string & tname,
 			Xapian::termpos tpos,
 			Xapian::termcount wdfinc)
 {
@@ -137,7 +137,7 @@
 }
 
 void
-Document::add_term(const string & tname, Xapian::termcount wdfinc)
+Document::add_term(const std::string & tname, Xapian::termcount wdfinc)
 {
     LOGCALL_VOID(API, "Document::add_term", tname | wdfinc);
     if (tname.empty()) {
@@ -147,7 +147,7 @@
 }
 
 void
-Document::remove_posting(const string & tname, Xapian::termpos tpos,
+Document::remove_posting(const std::string & tname, Xapian::termpos tpos,
 			 Xapian::termcount wdfdec)
 {
     LOGCALL_VOID(API, "Document::remove_posting", tname | tpos | wdfdec);
@@ -174,7 +174,7 @@
 }
 
 void
-Document::remove_term(const string & tname)
+Document::remove_term(const std::string & tname)
 {
     LOGCALL_VOID(API, "Document::remove_term", tname);
     internal->remove_term(tname);
@@ -296,7 +296,7 @@
 
     // Search for the position the term occurs at.  Use binary chop to
     // search, since this is a sorted list.
-    vector<Xapian::termpos>::iterator i;
+    std::vector<Xapian::termpos>::iterator i;
     i = lower_bound(positions.begin(), positions.end(), tpos);
     if (i == positions.end() || *i != tpos) {
 	auto new_split = positions.size();
@@ -387,7 +387,7 @@
 string
 OmDocumentTerm::get_description() const
 {
-    string description;
+    std::string description;
     description = "OmDocumentTerm(wdf = ";
     description += str(wdf);
     description += ", positions[";
@@ -400,7 +400,7 @@
 Xapian::Document::Internal::get_value(Xapian::valueno slot) const
 {
     if (values_here) {
-	map<Xapian::valueno, string>::const_iterator i;
+	std::map<Xapian::valueno, string>::const_iterator i;
 	i = values.find(slot);
 	if (i == values.end()) return string();
 	return i->second;
@@ -419,7 +419,7 @@
 }
 
 void
-Xapian::Document::Internal::set_data(const string &data_)
+Xapian::Document::Internal::set_data(const std::string &data_)
 {
     data = data_;
     data_here = true;
@@ -437,7 +437,7 @@
 }
 
 void
-Xapian::Document::Internal::add_value(Xapian::valueno slot, const string &value)
+Xapian::Document::Internal::add_value(Xapian::valueno slot, const std::string &value)
 {
     need_values();
     if (!value.empty()) {
@@ -453,7 +453,7 @@
 Xapian::Document::Internal::remove_value(Xapian::valueno slot)
 {
     need_values();
-    map<Xapian::valueno, string>::iterator i = values.find(slot);
+    std::map<Xapian::valueno, string>::iterator i = values.find(slot);
     if (i == values.end()) {
 	throw Xapian::InvalidArgumentError("Value #" + str(slot) +
 		" is not present in document, in "
@@ -470,13 +470,13 @@
 }
 
 void
-Xapian::Document::Internal::add_posting(const string & tname, Xapian::termpos tpos,
+Xapian::Document::Internal::add_posting(const std::string & tname, Xapian::termpos tpos,
 			      Xapian::termcount wdfinc)
 {
     need_terms();
     positions_modified = true;
 
-    map<string, OmDocumentTerm>::iterator i;
+    std::map<string, OmDocumentTerm>::iterator i;
     i = terms.find(tname);
     if (i == terms.end()) {
 	++termlist_size;
@@ -490,11 +490,11 @@
 }
 
 void
-Xapian::Document::Internal::add_term(const string & tname, Xapian::termcount wdfinc)
+Xapian::Document::Internal::add_term(const std::string & tname, Xapian::termcount wdfinc)
 {
     need_terms();
 
-    map<string, OmDocumentTerm>::iterator i;
+    std::map<string, OmDocumentTerm>::iterator i;
     i = terms.find(tname);
     if (i == terms.end()) {
 	++termlist_size;
@@ -507,13 +507,13 @@
 }
 
 void
-Xapian::Document::Internal::remove_posting(const string & tname,
+Xapian::Document::Internal::remove_posting(const std::string & tname,
 					   Xapian::termpos tpos,
 					   Xapian::termcount wdfdec)
 {
     need_terms();
 
-    map<string, OmDocumentTerm>::iterator i;
+    std::map<string, OmDocumentTerm>::iterator i;
     i = terms.find(tname);
     if (i == terms.end() || i->second.is_deleted()) {
 	if (tname.empty())
@@ -559,10 +559,10 @@
 }
 
 void
-Xapian::Document::Internal::remove_term(const string & tname)
+Xapian::Document::Internal::remove_term(const std::string & tname)
 {
     need_terms();
-    map<string, OmDocumentTerm>::iterator i;
+    std::map<string, OmDocumentTerm>::iterator i;
     i = terms.find(tname);
     if (i == terms.end() || i->second.is_deleted()) {
 	if (tname.empty())
@@ -633,7 +633,7 @@
 string
 Xapian::Document::Internal::get_description() const
 {
-    string desc = "Document(";
+    std::string desc = "Document(";
 
     // description_append ?
     if (data_here) {
diff -ur xapian-core-1.4.21/api/omenquire.cc xapian-core-1.4.21/api/omenquire.cc
--- xapian-core-1.4.21/api/omenquire.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/omenquire.cc	2022-11-08 16:44:15.476461514 +0100
@@ -128,7 +128,7 @@
 string
 RSet::Internal::get_description() const
 {
-    string description("RSet::Internal(");
+    std::string description("RSet::Internal(");
 
     set<Xapian::docid>::const_iterator i;
     for (i = items.begin(); i != items.end(); ++i) {
@@ -148,7 +148,7 @@
 string
 MSetItem::get_description() const
 {
-    string description;
+    std::string description;
 
     description = str(did) + ", " + str(wt) + ", " +
 	    collapse_key;
@@ -203,7 +203,7 @@
 }
 
 Xapian::doccount
-MSet::get_termfreq(const string &tname) const
+MSet::get_termfreq(const std::string &tname) const
 {
     LOGCALL(API, Xapian::doccount, "Xapian::MSet::get_termfreq", tname);
     Assert(internal.get() != 0);
@@ -219,7 +219,7 @@
 }
 
 double
-MSet::get_termweight(const string &tname) const
+MSet::get_termweight(const std::string &tname) const
 {
     LOGCALL(API, double, "Xapian::MSet::get_termweight", tname);
     Assert(internal.get() != 0);
@@ -228,7 +228,7 @@
     }
     double termweight;
     if (!internal->stats->get_termweight(tname, termweight)) {
-	string msg = tname;
+	std::string msg = tname;
 	msg += ": termweight not available";
 	throw InvalidArgumentError(msg);
     }
@@ -301,13 +301,13 @@
 }
 
 string
-MSet::snippet(const string & text,
+MSet::snippet(const std::string & text,
 	      size_t length,
 	      const Xapian::Stem & stemmer,
 	      unsigned flags,
-	      const string & hi_start,
-	      const string & hi_end,
-	      const string & omit) const
+	      const std::string & hi_start,
+	      const std::string & hi_end,
+	      const std::string & omit) const
 {
     Assert(internal.get() != 0);
     return internal->snippet(text, length, stemmer, flags,
@@ -351,7 +351,7 @@
 {
     LOGCALL(MATCH, Document, "Xapian::MSet::Internal::get_doc_by_index", index);
     index += firstitem;
-    map<Xapian::doccount, Document>::const_iterator doc;
+    std::map<Xapian::doccount, Document>::const_iterator doc;
     doc = indexeddocs.find(index);
     if (doc != indexeddocs.end()) {
 	RETURN(doc->second);
@@ -384,7 +384,7 @@
     if (last > items.size() - 1)
 	last = items.size() - 1;
     for (Xapian::doccount i = first; i <= last; ++i) {
-	map<Xapian::doccount, Document>::const_iterator doc;
+	std::map<Xapian::doccount, Document>::const_iterator doc;
 	doc = indexeddocs.find(i);
 	if (doc == indexeddocs.end()) {
 	    /* We don't have the document cached */
@@ -402,7 +402,7 @@
 string
 MSet::Internal::get_description() const
 {
-    string description = "Xapian::MSet::Internal(";
+    std::string description = "Xapian::MSet::Internal(";
 
     description += "firstitem=" + str(firstitem) + ", " +
 	    "matches_lower_bound=" + str(matches_lower_bound) + ", " +
@@ -639,13 +639,13 @@
 
 class ByQueryIndexCmp {
   private:
-    typedef map<string, unsigned int> tmap_t;
+    typedef std::map<string, unsigned int> tmap_t;
     const tmap_t &tmap;
 
   public:
     explicit ByQueryIndexCmp(const tmap_t &tmap_) : tmap(tmap_) {}
-    bool operator()(const string &left,
-		    const string &right) const {
+    bool operator()(const std::string &left,
+		    const std::string &right) const {
 	tmap_t::const_iterator l, r;
 	l = tmap.find(left);
 	r = tmap.find(right);
@@ -667,26 +667,26 @@
     // copy the list of query terms into a map for faster access.
     // FIXME: a hash would be faster than a map, if this becomes
     // a problem.
-    map<string, unsigned int> tmap;
+    std::map<string, unsigned int> tmap;
     unsigned int index = 1;
     for ( ; qt != query.get_terms_end(); ++qt) {
 	if (tmap.find(*qt) == tmap.end())
 	    tmap[*qt] = index++;
     }
 
-    vector<string> matching_terms;
+    std::vector<string> matching_terms;
 
     TermIterator docterms = db.termlist_begin(did);
     TermIterator docterms_end = db.termlist_end(did);
     while (docterms != docterms_end) {
-	string term = *docterms;
-	map<string, unsigned int>::iterator t = tmap.find(term);
+	std::string term = *docterms;
+	std::map<string, unsigned int>::iterator t = tmap.find(term);
 	if (t != tmap.end()) matching_terms.push_back(term);
 	++docterms;
     }
 
     // sort the resulting list by query position.
-    sort(matching_terms.begin(), matching_terms.end(), ByQueryIndexCmp(tmap));
+    std::sort(matching_terms.begin(), matching_terms.end(), ByQueryIndexCmp(tmap));
 
     return TermIterator(new VectorTermList(matching_terms.begin(),
 					   matching_terms.end()));
@@ -701,7 +701,7 @@
 }
 
 Xapian::doccount
-Enquire::Internal::get_termfreq(const string &tname) const
+Enquire::Internal::get_termfreq(const std::string &tname) const
 {
     return db.get_termfreq(tname);
 }
@@ -709,7 +709,7 @@
 string
 Enquire::Internal::get_description() const
 {
-    string description = db.get_description();
+    std::string description = db.get_description();
     description += ", ";
     description += query.get_description();
     return description;
diff -ur xapian-core-1.4.21/api/omenquireinternal.h xapian-core-1.4.21/api/omenquireinternal.h
--- xapian-core-1.4.21/api/omenquireinternal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/omenquireinternal.h	2022-11-08 16:44:01.020512905 +0100
@@ -40,7 +40,7 @@
 
 #include "weight/weightinternal.h"
 
-using namespace std;
+using std::string;
 
 class OmExpand;
 class MultiMatch;
@@ -60,10 +60,10 @@
 	MSetItem(double wt_, Xapian::docid did_)
 		: wt(wt_), did(did_), collapse_count(0) {}
 
-	MSetItem(double wt_, Xapian::docid did_, const string &key_)
+	MSetItem(double wt_, Xapian::docid did_, const std::string &key_)
 		: wt(wt_), did(did_), collapse_key(key_), collapse_count(0) {}
 
-	MSetItem(double wt_, Xapian::docid did_, const string &key_,
+	MSetItem(double wt_, Xapian::docid did_, const std::string &key_,
 		 Xapian::doccount collapse_count_)
 		: wt(wt_), did(did_), collapse_key(key_),
 		  collapse_count(collapse_count_) {}
@@ -93,7 +93,7 @@
 	 *  of each key value (apart from the null string) will be present in
 	 *  the items in the returned Xapian::MSet.
 	 */
-	string collapse_key;
+	std::string collapse_key;
 
 	/** Count of collapses done on collapse_key so far
 	 *
@@ -104,10 +104,10 @@
 	Xapian::doccount collapse_count;
 
 	/** Used when sorting by value. */
-	string sort_key;
+	std::string sort_key;
 
-	/// Return a string describing this object.
-	string get_description() const;
+	/// Return a std::string describing this object.
+	std::string get_description() const;
 };
 
 }
@@ -167,7 +167,7 @@
 	/// The parameter required for TradWeight query expansion.
 	double expand_k;
 
-	vector<Xapian::Internal::opt_intrusive_ptr<MatchSpy>> spies;
+	std::vector<Xapian::Internal::opt_intrusive_ptr<MatchSpy>> spies;
 
 	explicit Internal(const Xapian::Database &databases);
 	~Internal();
@@ -195,9 +195,9 @@
 	TermIterator get_matching_terms(Xapian::docid did) const;
 	TermIterator get_matching_terms(const Xapian::MSetIterator &it) const;
 
-	Xapian::doccount get_termfreq(const string &tname) const;
+	Xapian::doccount get_termfreq(const std::string &tname) const;
 
-	string get_description() const;
+	std::string get_description() const;
 };
 
 class MSet::Internal : public Xapian::Internal::intrusive_base {
@@ -209,10 +209,10 @@
 	/** The set of documents which have been requested but not yet
 	 *  collected.
 	 */
-	mutable set<Xapian::doccount> requested_docs;
+	mutable std::set<Xapian::doccount> requested_docs;
 
 	/// Cache of documents, indexed by MSet index.
-	mutable map<Xapian::doccount, Xapian::Document> indexeddocs;
+	mutable std::map<Xapian::doccount, Xapian::Document> indexeddocs;
 
 	/// Read and cache the documents so far requested.
 	void read_docs() const;
@@ -232,7 +232,7 @@
 	Xapian::Weight::Internal * stats;
 
 	/// A list of items comprising the (selected part of the) MSet.
-	vector<Xapian::Internal::MSetItem> items;
+	std::vector<Xapian::Internal::MSetItem> items;
 
 	/// Rank of first item in MSet.
 	Xapian::doccount firstitem;
@@ -276,7 +276,7 @@
 	     Xapian::doccount uncollapsed_estimated_,
 	     double max_possible_,
 	     double max_attained_,
-	     vector<Xapian::Internal::MSetItem> &items_,
+	     std::vector<Xapian::Internal::MSetItem> &items_,
 	     double percent_factor_)
 		: percent_factor(percent_factor_),
 		  stats(NULL),
@@ -307,8 +307,8 @@
 			    const std::string & hi_end,
 			    const std::string & omit) const;
 
-	/// Return a string describing this object.
-	string get_description() const;
+	/// Return a std::string describing this object.
+	std::string get_description() const;
 
 	/** Fetch items specified into the document cache.
 	 */
@@ -320,13 +320,13 @@
 
     private:
 	/// Items in the relevance set.
-	set<Xapian::docid> items;
+	std::set<Xapian::docid> items;
 
     public:
-	const set<Xapian::docid> & get_items() const { return items; }
+	const std::set<Xapian::docid> & get_items() const { return items; }
 
-	/// Return a string describing this object.
-	string get_description() const;
+	/// Return a std::string describing this object.
+	std::string get_description() const;
 };
 
 }
diff -ur xapian-core-1.4.21/api/positioniterator.cc xapian-core-1.4.21/api/positioniterator.cc
--- xapian-core-1.4.21/api/positioniterator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/positioniterator.cc	2022-11-08 16:44:15.460461571 +0100
@@ -112,7 +112,7 @@
 PositionIterator::get_description() const
 {
 #if 0 // FIXME: Add PositionIterator::Internal::get_description() method.
-    string desc = "PositionIterator(";
+    std::string desc = "PositionIterator(";
     if (internal)
 	desc += internal->get_description();
     desc += ')';
diff -ur xapian-core-1.4.21/api/postingiterator.cc xapian-core-1.4.21/api/postingiterator.cc
--- xapian-core-1.4.21/api/postingiterator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/postingiterator.cc	2022-11-08 16:44:15.472461529 +0100
@@ -159,7 +159,7 @@
 std::string
 PostingIterator::get_description() const
 {
-    string desc = "PostingIterator(";
+    std::string desc = "PostingIterator(";
     if (internal)
 	desc += internal->get_description();
     desc += ')';
diff -ur xapian-core-1.4.21/api/postingsource.cc xapian-core-1.4.21/api/postingsource.cc
--- xapian-core-1.4.21/api/postingsource.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/postingsource.cc	2022-11-08 16:44:15.456461586 +0100
@@ -99,7 +99,7 @@
 }
 
 PostingSource *
-PostingSource::unserialise(const string &) const
+PostingSource::unserialise(const std::string &) const
 {
     throw Xapian::UnimplementedError("unserialise() not supported for this PostingSource");
 }
@@ -256,7 +256,7 @@
 }
 
 ValueWeightPostingSource *
-ValueWeightPostingSource::unserialise(const string &s) const
+ValueWeightPostingSource::unserialise(const std::string &s) const
 {
     const char * p = s.data();
     const char * end = p + s.size();
@@ -275,7 +275,7 @@
 {
     ValuePostingSource::init(db_);
 
-    string upper_bound = get_database().get_value_upper_bound(get_slot());
+    std::string upper_bound = get_database().get_value_upper_bound(get_slot());
     if (upper_bound.empty()) {
 	// This should only happen if there are no entries, in which case the
 	// maxweight is 0.
@@ -288,7 +288,7 @@
 string
 ValueWeightPostingSource::get_description() const
 {
-    string desc("Xapian::ValueWeightPostingSource(slot=");
+    std::string desc("Xapian::ValueWeightPostingSource(slot=");
     desc += str(get_slot());
     desc += ")";
     return desc;
@@ -303,7 +303,7 @@
 }
 
 void
-ValueMapPostingSource::add_mapping(const string & key, double wt)
+ValueMapPostingSource::add_mapping(const std::string & key, double wt)
 {
     weight_map[key] = wt;
     max_weight_in_map = max(wt, max_weight_in_map);
@@ -325,7 +325,7 @@
 double
 ValueMapPostingSource::get_weight() const
 {
-    map<string, double>::const_iterator wit = weight_map.find(get_value());
+    std::map<string, double>::const_iterator wit = weight_map.find(get_value());
     if (wit == weight_map.end()) {
 	return default_weight;
     }
@@ -336,7 +336,7 @@
 ValueMapPostingSource::clone() const
 {
     AutoPtr<ValueMapPostingSource> res(new ValueMapPostingSource(get_slot()));
-    map<string, double>::const_iterator i;
+    std::map<string, double>::const_iterator i;
     for (i = weight_map.begin(); i != weight_map.end(); ++i) {
 	res->add_mapping(i->first, i->second);
     }
@@ -353,10 +353,10 @@
 string
 ValueMapPostingSource::serialise() const
 {
-    string result = encode_length(get_slot());
+    std::string result = encode_length(get_slot());
     result += serialise_double(default_weight);
 
-    map<string, double>::const_iterator i;
+    std::map<string, double>::const_iterator i;
     for (i = weight_map.begin(); i != weight_map.end(); ++i) {
 	result.append(encode_length(i->first.size()));
 	result.append(i->first);
@@ -367,7 +367,7 @@
 }
 
 ValueMapPostingSource *
-ValueMapPostingSource::unserialise(const string &s) const
+ValueMapPostingSource::unserialise(const std::string &s) const
 {
     const char * p = s.data();
     const char * end = p + s.size();
@@ -379,7 +379,7 @@
     while (p != end) {
 	size_t keylen;
 	decode_length_and_check(&p, end, keylen);
-	string key(p, keylen);
+	std::string key(p, keylen);
 	p += keylen;
 	res->add_mapping(key, unserialise_double(&p, end));
     }
@@ -396,7 +396,7 @@
 string
 ValueMapPostingSource::get_description() const
 {
-    string desc("Xapian::ValueMapPostingSource(slot=");
+    std::string desc("Xapian::ValueMapPostingSource(slot=");
     desc += str(get_slot());
     desc += ")";
     return desc;
@@ -521,7 +521,7 @@
 }
 
 FixedWeightPostingSource *
-FixedWeightPostingSource::unserialise(const string &s) const
+FixedWeightPostingSource::unserialise(const std::string &s) const
 {
     const char * p = s.data();
     const char * s_end = p + s.size();
@@ -544,7 +544,7 @@
 string
 FixedWeightPostingSource::get_description() const
 {
-    string desc("Xapian::FixedWeightPostingSource(wt=");
+    std::string desc("Xapian::FixedWeightPostingSource(wt=");
     desc += str(get_maxweight());
     desc += ")";
     return desc;
diff -ur xapian-core-1.4.21/api/postlist.cc xapian-core-1.4.21/api/postlist.cc
--- xapian-core-1.4.21/api/postlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/postlist.cc	2022-11-08 16:44:15.448461615 +0100
@@ -46,13 +46,13 @@
     throw Xapian::InvalidOperationError("get_wdf() not meaningful for this PostingIterator");
 }
 
-const string *
+const std::string *
 PostingIterator::Internal::get_sort_key() const
 {
     return NULL;
 }
 
-const string *
+const std::string *
 PostingIterator::Internal::get_collapse_key() const
 {
     return NULL;
diff -ur xapian-core-1.4.21/api/postlist.h xapian-core-1.4.21/api/postlist.h
--- xapian-core-1.4.21/api/postlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/postlist.h	2022-11-08 16:44:01.016512919 +0100
@@ -205,7 +205,7 @@
     /// Gather PositionList* objects for a subtree.
     virtual void gather_position_lists(OrPositionList* orposlist);
 
-    /// Return a string description of this object.
+    /// Return a std::string description of this object.
     virtual std::string get_description() const = 0;
 };
 
diff -ur xapian-core-1.4.21/api/query.cc xapian-core-1.4.21/api/query.cc
--- xapian-core-1.4.21/api/query.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/query.cc	2022-11-08 16:44:15.456461586 +0100
@@ -40,7 +40,7 @@
 
 const Query Query::MatchNothing;
 
-Query::Query(const string & term, Xapian::termcount wqf, Xapian::termpos pos)
+Query::Query(const std::string & term, Xapian::termcount wqf, Xapian::termpos pos)
     : internal(new Xapian::Internal::QueryTerm(term, wqf, pos))
 {
     LOGCALL_CTOR(API, "Query", term | wqf | pos);
@@ -137,12 +137,12 @@
     if (!internal.get())
 	return TermIterator();
 
-    vector<pair<Xapian::termpos, string>> terms;
+    std::vector<pair<Xapian::termpos, string>> terms;
     internal->gather_terms(static_cast<void*>(&terms));
     sort(terms.begin(), terms.end());
 
-    vector<string> v;
-    const string * old_term = NULL;
+    std::vector<string> v;
+    const std::string * old_term = NULL;
     Xapian::termpos old_pos = 0;
     for (auto && i : terms) {
 	// Remove duplicates (same term at the same position).
@@ -162,16 +162,16 @@
     if (!internal.get())
 	return TermIterator();
 
-    vector<pair<Xapian::termpos, string>> terms;
+    std::vector<pair<Xapian::termpos, string>> terms;
     internal->gather_terms(static_cast<void*>(&terms));
     sort(terms.begin(), terms.end(), [](
-		const pair<Xapian::termpos, string>& a,
-		const pair<Xapian::termpos, string>& b) {
+		const std::pair<Xapian::termpos, string>& a,
+		const std::pair<Xapian::termpos, string>& b) {
 	return a.second < b.second;
     });
 
-    vector<string> v;
-    const string * old_term = NULL;
+    std::vector<string> v;
+    const std::string * old_term = NULL;
     for (auto && i : terms) {
 	// Remove duplicate term names.
 	if (old_term && *old_term == i.second)
@@ -192,14 +192,14 @@
 string
 Query::serialise() const
 {
-    string result;
+    std::string result;
     if (internal.get())
 	internal->serialise(result);
     return result;
 }
 
 const Query
-Query::unserialise(const string & s, const Registry & reg)
+Query::unserialise(const std::string & s, const Registry & reg)
 {
     const char * p = s.data();
     const char * end = p + s.size();
@@ -231,7 +231,7 @@
 string
 Query::get_description() const
 {
-    string desc = "Query(";
+    std::string desc = "Query(";
     if (internal.get())
 	desc += internal->get_description();
     desc += ")";
diff -ur xapian-core-1.4.21/api/queryinternal.cc xapian-core-1.4.21/api/queryinternal.cc
--- xapian-core-1.4.21/api/queryinternal.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/queryinternal.cc	2022-11-08 16:44:15.468461543 +0100
@@ -122,7 +122,7 @@
   protected:
     QueryOptimiser* qopt;
 
-    vector<PostList*> pls;
+    std::vector<PostList*> pls;
 
   public:
     Context(QueryOptimiser* qopt_, size_t reserve);
@@ -199,7 +199,7 @@
 void
 OrContext::select_most_frequent(size_t set_size)
 {
-    vector<PostList*>::iterator begin = pls.begin();
+    std::vector<PostList*>::iterator begin = pls.begin();
     nth_element(begin, begin + set_size - 1, pls.end(),
 		ComparePostListTermFreqAscending());
     shrink(set_size);
@@ -307,10 +307,10 @@
 		  Xapian::termcount window_)
 	    : op_(op__), begin(begin_), end(end_), window(window_) { }
 
-	PostList * postlist(PostList * pl, const vector<PostList*>& pls) const;
+	PostList * postlist(PostList * pl, const std::vector<PostList*>& pls) const;
     };
 
-    list<PosFilter> pos_filters;
+    std::list<PosFilter> pos_filters;
 
     AutoPtr<OrContext> not_ctx;
 
@@ -342,10 +342,10 @@
 };
 
 PostList *
-AndContext::PosFilter::postlist(PostList * pl, const vector<PostList*>& pls) const
+AndContext::PosFilter::postlist(PostList * pl, const std::vector<PostList*>& pls) const
 try {
-    vector<PostList *>::const_iterator terms_begin = pls.begin() + begin;
-    vector<PostList *>::const_iterator terms_end = pls.begin() + end;
+    std::vector<PostList *>::const_iterator terms_begin = pls.begin() + begin;
+    std::vector<PostList *>::const_iterator terms_end = pls.begin() + end;
 
     if (op_ == Xapian::Query::OP_NEAR) {
 	pl = new NearPostList(pl, window, terms_begin, terms_end);
@@ -531,7 +531,7 @@
 	    }
 	    if (size_t(end - *p) < len)
 		throw SerialisationError("Not enough data");
-	    string term(*p, len);
+	    std::string term(*p, len);
 	    *p += len;
 
 	    int code = ((ch >> 4) & 0x03);
@@ -561,7 +561,7 @@
 	    }
 	    size_t len;
 	    decode_length_and_check(p, end, len);
-	    string begin(*p, len);
+	    std::string begin(*p, len);
 	    *p += len;
 	    if (ch & 0x10) {
 		// OP_VALUE_GE
@@ -570,7 +570,7 @@
 
 	    // OP_VALUE_RANGE
 	    decode_length_and_check(p, end, len);
-	    string end_(*p, len);
+	    std::string end_(*p, len);
 	    *p += len;
 	    if (begin.empty()) // FIXME: is this right?
 		return new Xapian::Internal::QueryValueLE(slot, end_);
@@ -595,7 +595,7 @@
 		    op combiner = static_cast<op>(*(*p)++);
 		    size_t len;
 		    decode_length_and_check(p, end, len);
-		    string pattern(*p, len);
+		    std::string pattern(*p, len);
 		    *p += len;
 		    return new Xapian::Internal::QueryWildcard(pattern,
 							       max_expansion,
@@ -605,12 +605,12 @@
 		case 0x0c: { // PostingSource
 		    size_t len;
 		    decode_length_and_check(p, end, len);
-		    string name(*p, len);
+		    std::string name(*p, len);
 		    *p += len;
 
 		    const PostingSource * reg_source = reg.get_posting_source(name);
 		    if (!reg_source) {
-			string m = "PostingSource ";
+			std::string m = "PostingSource ";
 			m += name;
 			m += " not registered";
 			throw SerialisationError(m);
@@ -644,7 +644,7 @@
 	    break;
 	}
     }
-    string msg = "Unknown Query serialisation: ";
+    std::string msg = "Unknown Query serialisation: ";
     msg += str(ch);
     throw SerialisationError(msg);
 }
@@ -684,7 +684,7 @@
 string
 QueryTerm::get_description() const
 {
-    string desc;
+    std::string desc;
     if (term.empty()) {
 	desc = "<alldocuments>";
     } else {
@@ -724,7 +724,7 @@
 string
 QueryPostingSource::get_description() const
 {
-    string desc = "PostingSource(";
+    std::string desc = "PostingSource(";
     desc += source->get_description();
     desc += ')';
     return desc;
@@ -759,7 +759,7 @@
 QueryScaleWeight::get_description() const
 {
     Assert(subquery.internal.get());
-    string desc = str(scale_factor);
+    std::string desc = str(scale_factor);
     desc += " * ";
     desc += subquery.internal->get_description();
     return desc;
@@ -816,7 +816,7 @@
     if (factor != 0.0)
 	qopt->inc_total_subqs();
     const Xapian::Database::Internal & db = qopt->db;
-    const string & lb = db.get_value_lower_bound(slot);
+    const std::string & lb = db.get_value_lower_bound(slot);
     if (lb.empty()) {
 	// This should only happen if there are no values in this slot (which
 	// could be because the backend just doesn't support values at all).
@@ -828,7 +828,7 @@
     if (end < lb) {
 	RETURN(new EmptyPostList);
     }
-    const string & ub = db.get_value_upper_bound(slot);
+    const std::string & ub = db.get_value_upper_bound(slot);
     if (begin > ub) {
 	RETURN(new EmptyPostList);
     }
@@ -843,7 +843,7 @@
 		RETURN(db.open_post_list(string()));
 	    }
 	    // Otherwise we can at least replace the lower bound with an empty
-	    // string for a small efficiency gain.
+	    // std::string for a small efficiency gain.
 	    RETURN(new ValueGePostList(&db, slot, string()));
 	}
 	RETURN(new ValueGePostList(&db, slot, begin));
@@ -875,7 +875,7 @@
 string
 QueryValueRange::get_description() const
 {
-    string desc = "VALUE_RANGE ";
+    std::string desc = "VALUE_RANGE ";
     desc += str(slot);
     desc += ' ';
     description_append(desc, begin);
@@ -891,7 +891,7 @@
     if (factor != 0.0)
 	qopt->inc_total_subqs();
     const Xapian::Database::Internal & db = qopt->db;
-    const string & lb = db.get_value_lower_bound(slot);
+    const std::string & lb = db.get_value_lower_bound(slot);
     if (lb.empty()) {
 	// This should only happen if there are no values in this slot (which
 	// could be because the backend just doesn't support values at all).
@@ -941,7 +941,7 @@
 string
 QueryValueLE::get_description() const
 {
-    string desc = "VALUE_LE ";
+    std::string desc = "VALUE_LE ";
     desc += str(slot);
     desc += ' ';
     description_append(desc, limit);
@@ -955,7 +955,7 @@
     if (factor != 0.0)
 	qopt->inc_total_subqs();
     const Xapian::Database::Internal & db = qopt->db;
-    const string & lb = db.get_value_lower_bound(slot);
+    const std::string & lb = db.get_value_lower_bound(slot);
     if (lb.empty()) {
 	// This should only happen if there are no values in this slot (which
 	// could be because the backend just doesn't support values at all).
@@ -1002,7 +1002,7 @@
 string
 QueryValueGE::get_description() const
 {
-    string desc = "VALUE_GE ";
+    std::string desc = "VALUE_GE ";
     desc += str(slot);
     desc += ' ';
     description_append(desc, limit);
@@ -1043,7 +1043,7 @@
 	    if (expansions_left-- == 0) {
 		if (max_type == Xapian::Query::WILDCARD_LIMIT_FIRST)
 		    break;
-		string msg("Wildcard ");
+		std::string msg("Wildcard ");
 		msg += pattern;
 		msg += "* expands to more than ";
 		msg += str(max_expansion);
@@ -1051,7 +1051,7 @@
 		throw Xapian::WildcardError(msg);
 	    }
 	}
-	const string & term = t->get_termname();
+	const std::string & term = t->get_termname();
 	ctx.add_postlist(qopt->open_lazy_post_list(term, 1, or_factor));
     }
 
@@ -1124,7 +1124,7 @@
 string
 QueryWildcard::get_description() const
 {
-    string desc = "WILDCARD ";
+    std::string desc = "WILDCARD ";
     switch (combiner) {
 	case Query::OP_SYNONYM:
 	    desc += "SYNONYM ";
@@ -1399,7 +1399,7 @@
 QueryBranch::get_description_helper(const char * op,
 				    Xapian::termcount parameter) const
 {
-    string desc = "(";
+    std::string desc = "(";
     QueryVector::const_iterator i;
     for (i = subqueries.begin(); i != subqueries.end(); ++i) {
 	if (desc.size() > 1) {
@@ -1497,11 +1497,11 @@
 {
     result += static_cast<char>(0x0c);
 
-    const string & n = source->name();
+    const std::string & n = source->name();
     result += encode_length(n.size());
     result += n;
 
-    const string & s = source->serialise();
+    const std::string & s = source->serialise();
     result += encode_length(s.size());
     result += s;
 }
@@ -2003,7 +2003,7 @@
 QuerySynonym::get_description() const
 {
     if (subqueries.size() == 1) {
-	string d = "(SYNONYM ";
+	std::string d = "(SYNONYM ";
 	d += subqueries[0].internal->get_description();
 	d += ")";
 	return d;
diff -ur xapian-core-1.4.21/api/registry.cc xapian-core-1.4.21/api/registry.cc
--- xapian-core-1.4.21/api/registry.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/registry.cc	2022-11-08 16:44:15.464461558 +0100
@@ -75,14 +75,14 @@
 
 template<class T>
 static inline void
-register_object(map<string, T*> & registry, const T & obj)
+register_object(std::map<string, T*> & registry, const T & obj)
 {
-    string name = obj.name();
+    std::string name = obj.name();
     if (rare(name.empty())) {
 	throw Xapian::InvalidOperationError("Unable to register object - name() method returned empty string");
     }
 
-    pair<typename map<string, T *>::iterator, bool> r;
+    std::pair<typename std::map<string, T *>::iterator, bool> r;
     r = registry.insert(make_pair(name, static_cast<T*>(NULL)));
     if (!r.second) {
 	// Existing element with this key, so replace the pointer with NULL
@@ -108,9 +108,9 @@
 
 template<class T>
 static inline const T *
-lookup_object(map<string, T*> registry, const string & name)
+lookup_object(std::map<string, T*> registry, const std::string & name)
 {
-    typename map<string, T*>::const_iterator i = registry.find(name);
+    typename std::map<string, T*>::const_iterator i = registry.find(name);
     if (i == registry.end()) {
 	return NULL;
     }
@@ -193,7 +193,7 @@
 void
 Registry::Internal::clear_weighting_schemes()
 {
-    map<string, Xapian::Weight*>::const_iterator i;
+    std::map<string, Xapian::Weight*>::const_iterator i;
     for (i = wtschemes.begin(); i != wtschemes.end(); ++i) {
 	delete i->second;
     }
@@ -202,7 +202,7 @@
 void
 Registry::Internal::clear_posting_sources()
 {
-    map<string, Xapian::PostingSource *>::const_iterator i;
+    std::map<string, Xapian::PostingSource *>::const_iterator i;
     for (i = postingsources.begin(); i != postingsources.end(); ++i) {
 	delete i->second;
     }
@@ -211,7 +211,7 @@
 void
 Registry::Internal::clear_match_spies()
 {
-    map<string, Xapian::MatchSpy *>::const_iterator i;
+    std::map<string, Xapian::MatchSpy *>::const_iterator i;
     for (i = matchspies.begin(); i != matchspies.end(); ++i) {
 	delete i->second;
     }
@@ -220,7 +220,7 @@
 void
 Registry::Internal::clear_lat_long_metrics()
 {
-    map<string, Xapian::LatLongMetric *>::const_iterator i;
+    std::map<string, Xapian::LatLongMetric *>::const_iterator i;
     for (i = lat_long_metrics.begin(); i != lat_long_metrics.end(); ++i) {
 	delete i->second;
     }
@@ -269,7 +269,7 @@
 }
 
 const Xapian::Weight *
-Registry::get_weighting_scheme(const string & name) const
+Registry::get_weighting_scheme(const std::string & name) const
 {
     LOGCALL(API, const Xapian::Weight *, "Xapian::Registry::get_weighting_scheme", name);
     RETURN(lookup_object(internal->wtschemes, name));
@@ -283,7 +283,7 @@
 }
 
 const Xapian::PostingSource *
-Registry::get_posting_source(const string & name) const
+Registry::get_posting_source(const std::string & name) const
 {
     LOGCALL(API, const Xapian::PostingSource *, "Xapian::Registry::get_posting_source", name);
     RETURN(lookup_object(internal->postingsources, name));
@@ -297,7 +297,7 @@
 }
 
 const Xapian::MatchSpy *
-Registry::get_match_spy(const string & name) const
+Registry::get_match_spy(const std::string & name) const
 {
     LOGCALL(API, const Xapian::MatchSpy *, "Xapian::Registry::get_match_spy", name);
     RETURN(lookup_object(internal->matchspies, name));
@@ -311,7 +311,7 @@
 }
 
 const Xapian::LatLongMetric *
-Registry::get_lat_long_metric(const string & name) const
+Registry::get_lat_long_metric(const std::string & name) const
 {
     LOGCALL(API, const Xapian::LatLongMetric *, "Xapian::Registry::get_lat_long_metric", name);
     RETURN(lookup_object(internal->lat_long_metrics, name));
diff -ur xapian-core-1.4.21/api/replication.cc xapian-core-1.4.21/api/replication.cc
--- xapian-core-1.4.21/api/replication.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/replication.cc	2022-11-08 16:44:15.460461571 +0100
@@ -68,7 +68,7 @@
 
 void
 DatabaseMaster::write_changesets_to_fd(int fd,
-				       const string & start_revision,
+				       const std::string & start_revision,
 				       ReplicationInfo * info) const
 {
     LOGCALL_VOID(REPLICA, "DatabaseMaster::write_changesets_to_fd", fd | start_revision | info);
@@ -90,7 +90,7 @@
 
     // Extract the UUID from start_revision and compare it to the database.
     bool need_whole_db = false;
-    string revision;
+    std::string revision;
     if (start_revision.empty()) {
 	need_whole_db = true;
     } else {
@@ -98,9 +98,9 @@
 	const char * end = ptr + start_revision.size();
 	size_t uuid_length;
 	decode_length_and_check(&ptr, end, uuid_length);
-	string request_uuid(ptr, uuid_length);
+	std::string request_uuid(ptr, uuid_length);
 	ptr += uuid_length;
-	string db_uuid = db.internal[0]->get_uuid();
+	std::string db_uuid = db.internal[0]->get_uuid();
 	if (request_uuid != db_uuid) {
 	    need_whole_db = true;
 	}
@@ -113,7 +113,7 @@
 string
 DatabaseMaster::get_description() const
 {
-    string desc = "DatabaseMaster(";
+    std::string desc = "DatabaseMaster(";
     description_append(desc, path);
     desc += ")";
     return desc;
@@ -128,7 +128,7 @@
     Internal(const Internal &);
 
     /// The path to the replica directory.
-    string path;
+    std::string path;
 
     /// The id of the currently live database in the replica (0 or 1).
     int live_id;
@@ -152,16 +152,16 @@
 
     /** The revision that the secondary database has been updated to.
      */
-    string offline_revision;
+    std::string offline_revision;
 
     /** The UUID of the secondary database.
      */
-    string offline_uuid;
+    std::string offline_uuid;
 
     /** The revision that the secondary database must reach before it can be
      *  made live.
      */
-    string offline_needed_revision;
+    std::string offline_needed_revision;
 
     /** The time at which a changeset was last applied to the live database.
      *
@@ -201,8 +201,8 @@
      */
     bool possibly_make_offline_live();
 
-    string get_replica_path(int id) const {
-	string p = path;
+    std::string get_replica_path(int id) const {
+	std::string p = path;
 	p += "/replica_";
 	p += char('0' + id);
 	return p;
@@ -210,13 +210,13 @@
 
   public:
     /// Open a new DatabaseReplica::Internal for the specified path.
-    explicit Internal(const string & path_);
+    explicit Internal(const std::string & path_);
 
     /// Destructor.
     ~Internal() { delete conn; }
 
-    /// Get a string describing the current revision of the replica.
-    string get_revision_info() const;
+    /// Get a std::string describing the current revision of the replica.
+    std::string get_revision_info() const;
 
     /// Set the file descriptor to read changesets from.
     void set_read_fd(int fd);
@@ -225,13 +225,13 @@
     bool apply_next_changeset(ReplicationInfo * info,
 			      double reader_close_time);
 
-    /// Return a string describing this object.
-    string get_description() const { return path; }
+    /// Return a std::string describing this object.
+    std::string get_description() const { return path; }
 };
 
 // Methods of DatabaseReplica
 
-DatabaseReplica::DatabaseReplica(const string & path)
+DatabaseReplica::DatabaseReplica(const std::string & path)
 	: internal(new DatabaseReplica::Internal(path))
 {
     LOGCALL_CTOR(REPLICA, "DatabaseReplica", path);
@@ -270,7 +270,7 @@
 string
 DatabaseReplica::get_description() const
 {
-    string desc("DatabaseReplica(");
+    std::string desc("DatabaseReplica(");
     desc += internal->get_description();
     desc += ')';
     return desc;
@@ -281,9 +281,9 @@
 void
 DatabaseReplica::Internal::update_stub_database() const
 {
-    string stub_path = path;
+    std::string stub_path = path;
     stub_path += "/XAPIANDB";
-    string tmp_path = stub_path;
+    std::string tmp_path = stub_path;
     tmp_path += ".tmp";
     {
 	ofstream stub(tmp_path.c_str());
@@ -291,13 +291,13 @@
 		"auto replica_" << live_id << endl;
     }
     if (!io_tmp_rename(tmp_path, stub_path)) {
-	string msg("Failed to update stub db file for replica: ");
+	std::string msg("Failed to update stub db file for replica: ");
 	msg += path;
 	throw Xapian::DatabaseOpeningError(msg, errno);
     }
 }
 
-DatabaseReplica::Internal::Internal(const string & path_)
+DatabaseReplica::Internal::Internal(const std::string & path_)
 	: path(path_), live_id(0), live_db(), have_offline_db(false),
 	  need_copy_next(false), offline_revision(), offline_needed_revision(),
 	  last_live_changeset_time(), conn(NULL)
@@ -323,7 +323,7 @@
 	if (!dir_exists(path)) {
 	    throw DatabaseOpeningError("Replica path must be a directory");
 	}
-	string stub_path = path;
+	std::string stub_path = path;
 	stub_path += "/XAPIANDB";
 	try {
 	    live_db = WritableDatabase(stub_path,
@@ -336,7 +336,7 @@
 	}
 	// FIXME: simplify all this?
 	ifstream stub(stub_path.c_str());
-	string line;
+	std::string line;
 	while (getline(stub, line)) {
 	    if (!line.empty() && line[0] != '#') {
 		live_id = line[line.size() - 1] - '0';
@@ -358,8 +358,8 @@
 
     if (live_db.internal[0].get() == NULL) RETURN(string());
 
-    string uuid = (live_db.internal[0])->get_uuid();
-    string buf = encode_length(uuid.size());
+    std::string uuid = (live_db.internal[0])->get_uuid();
+    std::string buf = encode_length(uuid.size());
     buf += uuid;
     buf += (live_db.internal[0])->get_revision_info();
     RETURN(buf);
@@ -378,7 +378,7 @@
 {
     have_offline_db = true;
     last_live_changeset_time = 0;
-    string offline_path = get_replica_path(live_id ^ 1);
+    std::string offline_path = get_replica_path(live_id ^ 1);
     // If there's already an offline database, discard it.  This happens if one
     // copy of the database was sent, but further updates were needed before it
     // could be made live, and the remote end was then unable to send those
@@ -391,7 +391,7 @@
     }
 
     {
-	string buf;
+	std::string buf;
 	int type = conn->get_message(buf, end_time);
 	check_message_type(type, REPL_REPLY_DB_HEADER);
 	const char * ptr = buf.data();
@@ -404,7 +404,7 @@
 
     // Now, read the files for the database from the connection and create it.
     while (true) {
-	string filename;
+	std::string filename;
 	int type = conn->sniff_next_message_type(end_time);
 	if (type < 0 || type == REPL_REPLY_FAIL)
 	    return;
@@ -424,7 +424,7 @@
 	if (type < 0 || type == REPL_REPLY_FAIL)
 	    return;
 
-	string filepath = offline_path + "/" + filename;
+	std::string filepath = offline_path + "/" + filename;
 	type = conn->receive_file(filepath, end_time);
 	if (type < 0)
 	    throw_connection_closed_unexpectedly();
@@ -441,7 +441,7 @@
     if (type != expected) {
 	if (type < 0)
 	    throw_connection_closed_unexpectedly();
-	string m = "Expected replication protocol message type #";
+	std::string m = "Expected replication protocol message type #";
 	m += str(expected);
 	m += ", got #";
 	m += str(type);
@@ -452,7 +452,7 @@
 bool
 DatabaseReplica::Internal::possibly_make_offline_live()
 {
-    string replica_path(get_replica_path(live_id ^ 1));
+    std::string replica_path(get_replica_path(live_id ^ 1));
     AutoPtr<DatabaseReplicator> replicator;
     try {
 	replicator.reset(DatabaseReplicator::open(replica_path));
@@ -467,7 +467,7 @@
 	return false;
     }
 
-    string replicated_uuid = replicator->get_uuid();
+    std::string replicated_uuid = replicator->get_uuid();
     if (replicated_uuid.empty()) {
 	return false;
     }
@@ -502,7 +502,7 @@
 	int type = conn->sniff_next_message_type(0.0);
 	switch (type) {
 	    case REPL_REPLY_END_OF_CHANGES: {
-		string buf;
+		std::string buf;
 		type = conn->get_message(buf, 0.0);
 		check_message_type(type, REPL_REPLY_END_OF_CHANGES);
 		RETURN(false);
@@ -513,7 +513,7 @@
 		    apply_db_copy(0.0);
 		    if (info != NULL)
 			++(info->fullcopy_count);
-		    string replica_uuid;
+		    std::string replica_uuid;
 		    {
 			AutoPtr<DatabaseReplicator> replicator(
 				DatabaseReplicator::open(get_replica_path(live_id ^ 1)));
@@ -544,7 +544,7 @@
 		}
 		if (!have_offline_db) {
 		    // Close the live db.
-		    string replica_path(get_replica_path(live_id));
+		    std::string replica_path(get_replica_path(live_id));
 		    live_db = WritableDatabase();
 
 		    if (last_live_changeset_time != 0.0) {
@@ -595,7 +595,7 @@
 		}
 		RETURN(true);
 	    case REPL_REPLY_FAIL: {
-		string buf;
+		std::string buf;
 		if (conn->get_message(buf, 0.0) < 0)
 		    throw_connection_closed_unexpectedly();
 		throw NetworkError("Unable to fully synchronise: " + buf);
diff -ur xapian-core-1.4.21/api/replication.h xapian-core-1.4.21/api/replication.h
--- xapian-core-1.4.21/api/replication.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/replication.h	2022-11-08 16:44:01.020512905 +0100
@@ -89,7 +89,7 @@
      *
      *  @param start_revision The starting revision of the database that the
      *                  changesets are to be applied to.  Specify an empty
-     *                  string to get a "creation" changeset, which
+     *                  std::string to get a "creation" changeset, which
      *                  includes the creation of the database.  The
      *                  revision will include the unique identifier for the
      *                  database, if one is available.
@@ -102,7 +102,7 @@
 				const std::string & start_revision,
 				ReplicationInfo * info) const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -141,7 +141,7 @@
      */
     explicit DatabaseReplica(const std::string & path);
 
-    /** Get a string describing the current revision of the replica.
+    /** Get a std::string describing the current revision of the replica.
      *
      *  The revision information includes a unique identifier for the master
      *  database that the replica is of, as well as information about the exact
@@ -193,7 +193,7 @@
     bool apply_next_changeset(ReplicationInfo * info,
 			      double reader_close_time);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/api/roundestimate.h xapian-core-1.4.21/api/roundestimate.h
--- xapian-core-1.4.21/api/roundestimate.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/roundestimate.h	2022-11-08 16:44:01.016512919 +0100
@@ -36,13 +36,13 @@
 inline Xapian::doccount
 round_estimate(T lb, T ub, T est)
 {
-    using namespace std;
+    using std::string;
 
     // We round based on the difference between the bounds, or the estimate if
     // that's smaller - for example, consider lb=11, est=24, ub=1234 where
     // rounding est to a multiple of 10 is reasonable but rounding it to a
     // multiple of 1000 isn't.
-    T scale = min(ub - lb, est);
+    T scale = std::min(ub - lb, est);
     if (scale <= 10) {
 	// Estimate is either too close to exact or too small to round.
 	return est;
diff -ur xapian-core-1.4.21/api/sortable-serialise.cc xapian-core-1.4.21/api/sortable-serialise.cc
--- xapian-core-1.4.21/api/sortable-serialise.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/sortable-serialise.cc	2022-11-08 16:44:15.472461529 +0100
@@ -1,5 +1,5 @@
 /** @file
- * @brief Serialise floating point values to string which sort the same way.
+ * @brief Serialise floating point values to std::string which sort the same way.
  */
 /* Copyright (C) 2007,2009,2015,2016 Olly Betts
  *
@@ -174,7 +174,7 @@
 }
 
 /// Get a number from the character at a given position in a string, returning
-/// 0 if the string isn't long enough.
+/// 0 if the std::string isn't long enough.
 static inline unsigned char
 numfromstr(const std::string & str, std::string::size_type pos)
 {
diff -ur xapian-core-1.4.21/api/termiterator.cc xapian-core-1.4.21/api/termiterator.cc
--- xapian-core-1.4.21/api/termiterator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/termiterator.cc	2022-11-08 16:44:15.452461600 +0100
@@ -138,7 +138,7 @@
 }
 
 void
-TermIterator::skip_to(const string & term)
+TermIterator::skip_to(const std::string & term)
 {
     LOGCALL_VOID(API, "TermIterator::skip_to", term);
     if (internal)
@@ -149,7 +149,7 @@
 TermIterator::get_description() const
 {
 #if 0 // FIXME: Add TermIterator::Internal::get_description() method.
-    string desc = "TermIterator(";
+    std::string desc = "TermIterator(";
     if (internal)
 	desc += internal->get_description();
     desc += ')';
diff -ur xapian-core-1.4.21/api/termlist.cc xapian-core-1.4.21/api/termlist.cc
--- xapian-core-1.4.21/api/termlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/termlist.cc	2022-11-08 16:44:15.460461571 +0100
@@ -37,7 +37,7 @@
     Assert(false);
 }
 
-// Default implementation for when the positions aren't in vector<termpos>.
+// Default implementation for when the positions aren't in std::vector<termpos>.
 const std::vector<Xapian::termpos> *
 TermIterator::Internal::get_vector_termpos() const
 {
diff -ur xapian-core-1.4.21/api/termlist.h xapian-core-1.4.21/api/termlist.h
--- xapian-core-1.4.21/api/termlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/termlist.h	2022-11-08 16:44:01.012512934 +0100
@@ -94,13 +94,13 @@
     /// Return the length of the position list for the current position.
     virtual Xapian::termcount positionlist_count() const = 0;
 
-    /** Get pointer to vector<termpos> if that's the internal representation.
+    /** Get pointer to std::vector<termpos> if that's the internal representation.
      *
      *  This avoids unnecessary copying of positions in the common cases - the
      *  case it doesn't help with is adding a document back with unmodified
      *  positions *AND* a different docid, which is an unusual thing to do.
      *
-     *  @return Pointer to vector<termpos> or NULL.
+     *  @return Pointer to std::vector<termpos> or NULL.
      */
     virtual const std::vector<Xapian::termpos> * get_vector_termpos() const;
 
diff -ur xapian-core-1.4.21/api/valueiterator.cc xapian-core-1.4.21/api/valueiterator.cc
--- xapian-core-1.4.21/api/valueiterator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/valueiterator.cc	2022-11-08 16:44:15.460461571 +0100
@@ -144,7 +144,7 @@
 std::string
 ValueIterator::get_description() const
 {
-    string desc = "ValueIterator(";
+    std::string desc = "ValueIterator(";
     if (internal)
 	desc += internal->get_description();
     desc += ')';
diff -ur xapian-core-1.4.21/api/valuerangeproc.cc xapian-core-1.4.21/api/valuerangeproc.cc
--- xapian-core-1.4.21/api/valuerangeproc.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/valuerangeproc.cc	2022-11-08 16:44:15.456461586 +0100
@@ -33,7 +33,7 @@
 namespace Xapian {
 
 Xapian::valueno
-StringValueRangeProcessor::operator()(string &begin, string &end)
+StringValueRangeProcessor::operator()(string &begin, std::string &end)
 {
     if (str.size()) {
 	if (prefix) {
@@ -64,7 +64,7 @@
 }
 
 static bool
-decode_xxy(const string & s, int & x1, int &x2, int &y)
+decode_xxy(const std::string & s, int & x1, int &x2, int &y)
 {
     if (s.size() == 0) {
 	x1 = x2 = y = -1;
@@ -108,7 +108,7 @@
 
 // NB Assumes the length has been checked to be 10 already.
 static bool
-is_yyyy_mm_dd(const string &s)
+is_yyyy_mm_dd(const std::string &s)
 {
     return (s.find_first_not_of("0123456789") == 4 &&
 	    s.find_first_not_of("0123456789", 5) == 7 &&
@@ -141,7 +141,7 @@
 }
 
 Xapian::valueno
-DateValueRangeProcessor::operator()(string &begin, string &end)
+DateValueRangeProcessor::operator()(string &begin, std::string &end)
 {
     if (StringValueRangeProcessor::operator()(begin, end) == BAD_VALUENO)
 	return BAD_VALUENO;
@@ -212,7 +212,7 @@
 }
 
 Xapian::valueno
-NumberValueRangeProcessor::operator()(string &begin, string &end)
+NumberValueRangeProcessor::operator()(string &begin, std::string &end)
 {
     if (StringValueRangeProcessor::operator()(begin, end) == BAD_VALUENO)
 	return BAD_VALUENO;
@@ -321,7 +321,7 @@
 	(e.size() == 10 || e.size() == 0)) {
 	if ((b.empty() || is_yyyy_mm_dd(b)) &&
 	    (e.empty() || is_yyyy_mm_dd(e))) {
-	    string begin = b, end = e;
+	    std::string begin = b, end = e;
 	    // YYYY-MM-DD
 	    if (!begin.empty()) {
 		begin.erase(7, 1);
@@ -396,7 +396,7 @@
 	char * endptr;
 	num_b = strtod(startptr, &endptr);
 	if (endptr != startptr + b.size() || errno) {
-	    // Invalid characters in string || overflow or underflow.
+	    // Invalid characters in std::string || overflow or underflow.
 	    goto not_our_range;
 	}
     } else {
@@ -410,7 +410,7 @@
 	char * endptr;
 	num_e = strtod(startptr, &endptr);
 	if (endptr != startptr + e.size() || errno) {
-	    // Invalid characters in string || overflow or underflow.
+	    // Invalid characters in std::string || overflow or underflow.
 	    goto not_our_range;
 	}
     } else {
diff -ur xapian-core-1.4.21/api/valuesetmatchdecider.cc xapian-core-1.4.21/api/valuesetmatchdecider.cc
--- xapian-core-1.4.21/api/valuesetmatchdecider.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/valuesetmatchdecider.cc	2022-11-08 16:44:15.480461501 +0100
@@ -33,7 +33,7 @@
 bool
 ValueSetMatchDecider::operator()(const Xapian::Document& doc) const
 {
-    string value = doc.get_value(valuenum);
+    std::string value = doc.get_value(valuenum);
     set<string>::const_iterator it = testset.find(value);
     if (inclusive)
 	return it != testset.end();
diff -ur xapian-core-1.4.21/api/vectortermlist.cc xapian-core-1.4.21/api/vectortermlist.cc
--- xapian-core-1.4.21/api/vectortermlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/vectortermlist.cc	2022-11-08 16:44:15.472461529 +0100
@@ -79,7 +79,7 @@
 }
 
 TermList *
-VectorTermList::skip_to(const string &)
+VectorTermList::skip_to(const std::string &)
 {
     // skip_to only makes sense for termlists which are in sorted order.
     throw Xapian::InvalidOperationError("VectorTermList::skip_to() not meaningful");
diff -ur xapian-core-1.4.21/api/vectortermlist.h xapian-core-1.4.21/api/vectortermlist.h
--- xapian-core-1.4.21/api/vectortermlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/api/vectortermlist.h	2022-11-08 16:44:01.016512919 +0100
@@ -28,7 +28,7 @@
 
 /** This class stores a list of terms.
  *
- *  To be memory efficient, we store the terms in a single string using a
+ *  To be memory efficient, we store the terms in a single std::string using a
  *  suitable simple encoding.  This way the number of bytes needed will
  *  usually be the sum of the lengths of all the terms plus the number of
  *  terms.  If we used std::vector<std::string> here like we used to, that
diff -ur xapian-core-1.4.21/backends/byte_length_strings.h xapian-core-1.4.21/backends/byte_length_strings.h
--- xapian-core-1.4.21/backends/byte_length_strings.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/byte_length_strings.h	2022-11-08 16:44:00.968513089 +0100
@@ -75,7 +75,7 @@
 };
 
 struct ByteLengthPrefixedStringItorGt {
-    /// Return true if and only if a's string is strictly greater than b's.
+    /// Return true if and only if a's std::string is strictly greater than b's.
     bool operator()(const ByteLengthPrefixedStringItor *a,
 		    const ByteLengthPrefixedStringItor *b) const {
 	return (**a > **b);
diff -ur xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.cc xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.cc
--- xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.cc	2022-11-08 16:44:15.388461828 +0100
@@ -31,7 +31,7 @@
 
 ChertAllDocsModifiedPostList::ChertAllDocsModifiedPostList(intrusive_ptr<const ChertDatabase> db_,
 							   Xapian::doccount doccount_,
-							   const map<Xapian::docid, Xapian::termcount> & doclens_)
+							   const std::map<Xapian::docid, Xapian::termcount> & doclens_)
 	: ChertAllDocsPostList(db_, doccount_),
 	  doclens(doclens_),
 	  doclens_it(doclens.begin())
@@ -137,7 +137,7 @@
 string
 ChertAllDocsModifiedPostList::get_description() const
 {
-    string desc = "ChertAllDocsModifiedPostList(did=";
+    std::string desc = "ChertAllDocsModifiedPostList(did=";
     desc += str(get_docid());
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.h xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.h
--- xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_alldocsmodifiedpostlist.h	2022-11-08 16:44:00.952513146 +0100
@@ -28,10 +28,10 @@
 
 class ChertAllDocsModifiedPostList : public ChertAllDocsPostList {
     /// Modifications to apply to the ChertAllDocsPostList.
-    map<Xapian::docid, Xapian::termcount> doclens;
+    std::map<Xapian::docid, Xapian::termcount> doclens;
 
     /// Current position in the doclens list.
-    map<Xapian::docid, Xapian::termcount>::const_iterator doclens_it;
+    std::map<Xapian::docid, Xapian::termcount>::const_iterator doclens_it;
 
     /// Don't allow assignment.
     void operator=(const ChertAllDocsModifiedPostList &);
@@ -45,7 +45,7 @@
   public:
     ChertAllDocsModifiedPostList(Xapian::Internal::intrusive_ptr<const ChertDatabase> db_,
 				 Xapian::doccount doccount_,
-				 const map<Xapian::docid, Xapian::termcount> & doclens_);
+				 const std::map<Xapian::docid, Xapian::termcount> & doclens_);
 
     Xapian::docid get_docid() const;
 
diff -ur xapian-core-1.4.21/backends/chert/chert_alldocspostlist.cc xapian-core-1.4.21/backends/chert/chert_alldocspostlist.cc
--- xapian-core-1.4.21/backends/chert/chert_alldocspostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_alldocspostlist.cc	2022-11-08 16:44:15.404461770 +0100
@@ -80,7 +80,7 @@
 string
 ChertAllDocsPostList::get_description() const
 {
-    string desc = "ChertAllDocsPostList(did=";
+    std::string desc = "ChertAllDocsPostList(did=";
     desc += str(get_docid());
     desc += ",doccount=";
     desc += str(doccount);
diff -ur xapian-core-1.4.21/backends/chert/chert_alltermslist.cc xapian-core-1.4.21/backends/chert/chert_alltermslist.cc
--- xapian-core-1.4.21/backends/chert/chert_alltermslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_alltermslist.cc	2022-11-08 16:44:15.416461728 +0100
@@ -85,7 +85,7 @@
 	if (prefix.empty()) {
 	    (void)cursor->find_entry_ge(string("\x00\xff", 2));
 	} else {
-	    const string & key = pack_chert_postlist_key(prefix);
+	    const std::string & key = pack_chert_postlist_key(prefix);
 	    if (cursor->find_entry_ge(key)) {
 		// The exact term we asked for is there, so just copy it rather
 		// than wasting effort unpacking it from the key.
@@ -126,7 +126,7 @@
 }
 
 TermList *
-ChertAllTermsList::skip_to(const string &term)
+ChertAllTermsList::skip_to(const std::string &term)
 {
     LOGCALL(DB, TermList *, "ChertAllTermsList::skip_to", term);
     Assert(!at_end());
@@ -139,7 +139,7 @@
 	Assert(cursor); // The postlist table isn't optional.
     }
 
-    string key = pack_chert_postlist_key(term);
+    std::string key = pack_chert_postlist_key(term);
     if (cursor->find_entry_ge(key)) {
 	// The exact term we asked for is there, so just copy it rather than
 	// wasting effort unpacking it from the key.
diff -ur xapian-core-1.4.21/backends/chert/chert_btreebase.cc xapian-core-1.4.21/backends/chert/chert_btreebase.cc
--- xapian-core-1.4.21/backends/chert/chert_btreebase.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_btreebase.cc	2022-11-08 16:44:15.384461842 +0100
@@ -115,8 +115,8 @@
 /** Do most of the error handling from unpack_uint() */
 static bool
 do_unpack_uint(const char **start, const char *end,
-	       uint4 *dest, string &err_msg,
-	       const string &basename,
+	       uint4 *dest, std::string &err_msg,
+	       const std::string &basename,
 	       const char *varname)
 {
     bool result = unpack_uint(start, end, dest);
@@ -132,8 +132,8 @@
 
 static bool
 do_unpack_uint(const char **start, const char *end,
-	       chert_tablesize_t *dest, string &err_msg,
-	       const string &basename,
+	       chert_tablesize_t *dest, std::string &err_msg,
+	       const std::string &basename,
 	       const char *varname)
 {
     bool result = unpack_uint(start, end, dest);
@@ -163,10 +163,10 @@
 #define REASONABLE_BASE_SIZE 1024
 
 bool
-ChertTable_base::read(const string & name, char ch, bool read_bitmap,
-		      string &err_msg)
+ChertTable_base::read(const std::string & name, char ch, bool read_bitmap,
+		      std::string &err_msg)
 {
-    string basename = name + "base" + ch;
+    std::string basename = name + "base" + ch;
     FD h(posixy_open(basename.c_str(), O_RDONLY | O_CLOEXEC));
     if (h == -1) {
 	err_msg += "Couldn't open ";
@@ -276,15 +276,15 @@
 }
 
 void
-ChertTable_base::write_to_file(const string &filename,
+ChertTable_base::write_to_file(const std::string &filename,
 			       char base_letter,
-			       const string &tablename,
+			       const std::string &tablename,
 			       int changes_fd,
-			       const string * changes_tail)
+			       const std::string * changes_tail)
 {
     calculate_last_block();
 
-    string buf;
+    std::string buf;
     pack_uint(buf, revision);
     pack_uint(buf, CURR_FORMAT);
     pack_uint(buf, block_size);
@@ -303,7 +303,7 @@
 
     FD h(posixy_open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0666));
     if (h < 0) {
-	string message("Couldn't open base ");
+	std::string message("Couldn't open base ");
 	message += filename;
 	message += " to write: ";
 	errno_to_string(errno, message);
@@ -311,7 +311,7 @@
     }
 
     if (changes_fd >= 0) {
-	string changes_buf;
+	std::string changes_buf;
 	pack_uint(changes_buf, 1u); // Indicate the item is a base file.
 	pack_string(changes_buf, tablename);
 	changes_buf += base_letter; // The base file letter.
diff -ur xapian-core-1.4.21/backends/chert/chert_btreebase.h xapian-core-1.4.21/backends/chert/chert_btreebase.h
--- xapian-core-1.4.21/backends/chert/chert_btreebase.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_btreebase.h	2022-11-08 16:44:00.956513132 +0100
@@ -40,7 +40,7 @@
 	 *  @param name		The base of the filename
 	 *  @param ch		The suffix
 	 *  @param read_bitmap	True if we should read the bitmap
-	 *  @param err_msg	An error string which will be appended
+	 *  @param err_msg	An error std::string which will be appended
 	 *  			to for some errors instead of throwing
 	 *  			an exception.
 	 *
diff -ur xapian-core-1.4.21/backends/chert/chert_check.cc xapian-core-1.4.21/backends/chert/chert_check.cc
--- xapian-core-1.4.21/backends/chert/chert_check.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_check.cc	2022-11-08 16:44:15.400461785 +0100
@@ -49,10 +49,10 @@
 void ChertTableCheck::print_key(const uint8_t * p, int c, int j) const
 {
     Item item(p, c);
-    string key;
+    std::string key;
     if (item.key().length() >= 0)
 	item.key().read(&key);
-    string escaped;
+    std::string escaped;
     description_append(escaped, key);
     *out << escaped;
     if (j == 0) {
@@ -64,9 +64,9 @@
 {
     Item item(p, c);
     if (j == 0) {
-	string tag;
+	std::string tag;
 	item.append_chunk(&tag);
-	string escaped;
+	std::string escaped;
 	description_append(escaped, tag);
 	*out << '/' << item.components_of() << ' ' << escaped;
     } else {
@@ -232,18 +232,18 @@
 }
 
 void
-ChertTableCheck::check(const char * tablename, const string & path,
+ChertTableCheck::check(const char * tablename, const std::string & path,
 		       chert_revision_number_t * rev_ptr, int opts,
 		       ostream *out)
 {
-    string faked_base;
+    std::string faked_base;
 
     ChertTableCheck B(tablename, path, false, out);
     try {
 	if (rev_ptr && *rev_ptr) {
 	    // On failure, fake exception to be caught below.
 	    if (!B.open(*rev_ptr)) {
-		string msg = "Failed to open ";
+		std::string msg = "Failed to open ";
 		msg += tablename;
 		msg += " table at revision ";
 		msg += str(*rev_ptr);
@@ -371,7 +371,7 @@
 
 	// And retry the open.
 	if (!B.open(revision)) {
-	    string msg = "Root guess of blk ";
+	    std::string msg = "Root guess of blk ";
 	    msg += str(root);
 	    msg += " rev ";
 	    msg += str(revision);
@@ -450,7 +450,7 @@
 	    }
 	    B.base.set_item_count(B.check_item_count);
 	    B.base.set_sequential(B.check_sequential);
-	    string base_name = path;
+	    std::string base_name = path;
 	    base_name += "base";
 	    base_name += B.base_letter;
 	    B.base.write_to_file(base_name, B.base_letter, string(), -1, NULL);
@@ -462,7 +462,7 @@
 	    }
 
 	    if (B.check_item_count != B.get_entry_count()) {
-		string err = "Table entry count says ";
+		std::string err = "Table entry count says ";
 		err += str(B.get_entry_count());
 		err += " but actually counted ";
 		err += str(B.check_item_count);
diff -ur xapian-core-1.4.21/backends/chert/chert_compact.cc xapian-core-1.4.21/backends/chert/chert_compact.cc
--- xapian-core-1.4.21/backends/chert/chert_compact.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_compact.cc	2022-11-08 16:44:15.412461742 +0100
@@ -52,31 +52,31 @@
 namespace ChertCompact {
 
 static inline bool
-is_metainfo_key(const string & key)
+is_metainfo_key(const std::string & key)
 {
     return key.size() == 1 && key[0] == '\0';
 }
 
 static inline bool
-is_user_metadata_key(const string & key)
+is_user_metadata_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xc0';
 }
 
 static inline bool
-is_valuestats_key(const string & key)
+is_valuestats_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xd0';
 }
 
 static inline bool
-is_valuechunk_key(const string & key)
+is_valuechunk_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xd8';
 }
 
 static inline bool
-is_doclenchunk_key(const string & key)
+is_doclenchunk_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xe0';
 }
@@ -85,7 +85,7 @@
     Xapian::docid offset;
 
   public:
-    string key, tag;
+    std::string key, tag;
     Xapian::docid firstdid;
     Xapian::termcount tf, cf;
 
@@ -133,7 +133,7 @@
 	if (is_doclenchunk_key(key)) {
 	    d += 2;
 	} else {
-	    string tname;
+	    std::string tname;
 	    if (!unpack_string_preserving_sort(&d, e, tname))
 		throw Xapian::DatabaseCorruptError("Bad postlist key");
 	}
@@ -178,9 +178,9 @@
 
 static string
 encode_valuestats(Xapian::doccount freq,
-		  const string & lbound, const string & ubound)
+		  const std::string & lbound, const std::string & ubound)
 {
-    string value;
+    std::string value;
     pack_uint(value, freq);
     pack_string(value, lbound);
     // We don't store or count empty values, so neither of the bounds
@@ -192,7 +192,7 @@
 
 static void
 merge_postlists(Xapian::Compactor * compactor,
-		ChertTable * out, vector<Xapian::docid>::const_iterator offset,
+		ChertTable * out, std::vector<Xapian::docid>::const_iterator offset,
 		vector<ChertTable*>::const_iterator b,
 		vector<ChertTable*>::const_iterator e,
 		Xapian::docid last_docid)
@@ -201,7 +201,7 @@
     Xapian::termcount doclen_lbound = static_cast<Xapian::termcount>(-1);
     Xapian::termcount wdf_ubound = 0;
     Xapian::termcount doclen_ubound = 0;
-    priority_queue<PostlistCursor *, vector<PostlistCursor *>, PostlistCursorGt> pq;
+    priority_queue<PostlistCursor *, std::vector<PostlistCursor *>, PostlistCursorGt> pq;
     for ( ; b != e; ++b, ++offset) {
 	ChertTable *in = *b;
 	if (in->empty()) {
@@ -263,7 +263,7 @@
     if (last_docid) {
 	if (doclen_lbound > doclen_ubound)
 	    doclen_lbound = doclen_ubound;
-	string tag;
+	std::string tag;
 	pack_uint(tag, last_docid);
 	pack_uint(tag, doclen_lbound);
 	pack_uint(tag, wdf_ubound);
@@ -272,7 +272,7 @@
 	out->add(string(1, '\0'), tag);
     }
 
-    string last_key;
+    std::string last_key;
     {
 	// Merge user metadata.
 	vector<string> tags;
@@ -288,7 +288,7 @@
 			// FIXME: It would be better to merge all duplicates
 			// for a key in one call, but currently we don't in
 			// multipass mode.
-			const string & resolved_tag =
+			const std::string & resolved_tag =
 			    compactor->resolve_duplicate_metadata(last_key,
 								  tags.size(),
 								  &tags[0]);
@@ -314,7 +314,7 @@
 	if (!tags.empty()) {
 	    if (tags.size() > 1 && compactor) {
 		Assert(!last_key.empty());
-		const string & resolved_tag =
+		const std::string & resolved_tag =
 		    compactor->resolve_duplicate_metadata(last_key,
 							  tags.size(),
 							  &tags[0]);
@@ -330,7 +330,7 @@
     {
 	// Merge valuestats.
 	Xapian::doccount freq = 0;
-	string lbound, ubound;
+	std::string lbound, ubound;
 
 	while (!pq.empty()) {
 	    PostlistCursor * cur = pq.top();
@@ -347,13 +347,13 @@
 		last_key = key;
 	    }
 
-	    const string & tag = cur->tag;
+	    const std::string & tag = cur->tag;
 
 	    const char * pos = tag.data();
 	    const char * end = pos + tag.size();
 
 	    Xapian::doccount f;
-	    string l, u;
+	    std::string l, u;
 	    if (!unpack_uint(&pos, end, &f)) {
 		if (*pos == 0) throw Xapian::DatabaseCorruptError("Incomplete stats item in value table");
 		throw Xapian::RangeError("Frequency statistic in value table is too large");
@@ -394,7 +394,7 @@
     // Merge valuestream chunks.
     while (!pq.empty()) {
 	PostlistCursor * cur = pq.top();
-	const string & key = cur->key;
+	const std::string & key = cur->key;
 	if (!is_valuechunk_key(key)) break;
 	Assert(!is_user_metadata_key(key));
 	out->add(key, cur->tag);
@@ -407,7 +407,7 @@
     }
 
     Xapian::termcount tf = 0, cf = 0; // Initialise to avoid warnings.
-    vector<pair<Xapian::docid, string> > tags;
+    std::vector<pair<Xapian::docid, string> > tags;
     while (true) {
 	PostlistCursor * cur = NULL;
 	if (!pq.empty()) {
@@ -417,16 +417,16 @@
 	Assert(cur == NULL || !is_user_metadata_key(cur->key));
 	if (cur == NULL || cur->key != last_key) {
 	    if (!tags.empty()) {
-		string first_tag;
+		std::string first_tag;
 		pack_uint(first_tag, tf);
 		pack_uint(first_tag, cf);
 		pack_uint(first_tag, tags[0].first - 1);
-		string tag = tags[0].second;
+		std::string tag = tags[0].second;
 		tag[0] = (tags.size() == 1) ? '1' : '0';
 		first_tag += tag;
 		out->add(last_key, first_tag);
 
-		string term;
+		std::string term;
 		if (!is_doclenchunk_key(last_key)) {
 		    const char * p = last_key.data();
 		    const char * end = p + last_key.size();
@@ -479,7 +479,7 @@
 		vector<ChertTable*>::const_iterator b,
 		vector<ChertTable*>::const_iterator e)
 {
-    priority_queue<MergeCursor *, vector<MergeCursor *>, CursorGt> pq;
+    priority_queue<MergeCursor *, std::vector<MergeCursor *>, CursorGt> pq;
     for ( ; b != e; ++b) {
 	ChertTable *in = *b;
 	if (!in->empty()) {
@@ -491,7 +491,7 @@
 	MergeCursor * cur = pq.top();
 	pq.pop();
 
-	string key = cur->current_key;
+	std::string key = cur->current_key;
 	if (pq.empty() || pq.top()->current_key > key) {
 	    // No need to merge the tags, just copy the (possibly compressed)
 	    // tag value.
@@ -506,17 +506,17 @@
 	}
 
 	// Merge tag values with the same key:
-	string tag;
+	std::string tag;
 	if (key[0] != 'W') {
 	    // We just want the union of words, so copy over the first instance
 	    // and skip any identical ones.
 	    priority_queue<PrefixCompressedStringItor *,
-			   vector<PrefixCompressedStringItor *>,
+			   std::vector<PrefixCompressedStringItor *>,
 			   PrefixCompressedStringItorGt> pqtag;
 	    // Stick all the MergeCursor pointers in a vector because their
 	    // current_tag members must remain valid while we're merging their
 	    // tags, but we need to call next() on them all afterwards.
-	    vector<MergeCursor *> vec;
+	    std::vector<MergeCursor *> vec;
 	    vec.reserve(pq.size());
 
 	    while (true) {
@@ -529,11 +529,11 @@
 	    }
 
 	    PrefixCompressedStringWriter wr(tag);
-	    string lastword;
+	    std::string lastword;
 	    while (!pqtag.empty()) {
 		PrefixCompressedStringItor * it = pqtag.top();
 		pqtag.pop();
-		string word = **it;
+		std::string word = **it;
 		if (word != lastword) {
 		    lastword = word;
 		    wr.append(lastword);
@@ -546,7 +546,7 @@
 		}
 	    }
 
-	    vector<MergeCursor *>::const_iterator i;
+	    std::vector<MergeCursor *>::const_iterator i;
 	    for (i = vec.begin(); i != vec.end(); ++i) {
 		cur = *i;
 		if (cur->next()) {
@@ -585,10 +585,10 @@
 
 static void
 merge_synonyms(ChertTable * out,
-	       vector<ChertTable*>::const_iterator b,
-	       vector<ChertTable*>::const_iterator e)
+	       std::vector<ChertTable*>::const_iterator b,
+	       std::vector<ChertTable*>::const_iterator e)
 {
-    priority_queue<MergeCursor *, vector<MergeCursor *>, CursorGt> pq;
+    priority_queue<MergeCursor *, std::vector<MergeCursor *>, CursorGt> pq;
     for ( ; b != e; ++b) {
 	ChertTable *in = *b;
 	if (!in->empty()) {
@@ -600,7 +600,7 @@
 	MergeCursor * cur = pq.top();
 	pq.pop();
 
-	string key = cur->current_key;
+	std::string key = cur->current_key;
 	if (pq.empty() || pq.top()->current_key > key) {
 	    // No need to merge the tags, just copy the (possibly compressed)
 	    // tag value.
@@ -615,12 +615,12 @@
 	}
 
 	// Merge tag values with the same key:
-	string tag;
+	std::string tag;
 
 	// We just want the union of words, so copy over the first instance
 	// and skip any identical ones.
 	priority_queue<ByteLengthPrefixedStringItor *,
-		       vector<ByteLengthPrefixedStringItor *>,
+		       std::vector<ByteLengthPrefixedStringItor *>,
 		       ByteLengthPrefixedStringItorGt> pqtag;
 	vector<MergeCursor *> vec;
 
@@ -633,7 +633,7 @@
 	    pq.pop();
 	}
 
-	string lastword;
+	std::string lastword;
 	while (!pqtag.empty()) {
 	    ByteLengthPrefixedStringItor * it = pqtag.top();
 	    pqtag.pop();
@@ -667,8 +667,8 @@
 static void
 multimerge_postlists(Xapian::Compactor * compactor,
 		     ChertTable * out, const char * tmpdir,
-		     vector<ChertTable *> tmp,
-		     vector<Xapian::docid> off,
+		     std::vector<ChertTable *> tmp,
+		     std::vector<Xapian::docid> off,
 		     Xapian::docid last_docid)
 {
     unsigned int c = 0;
@@ -681,7 +681,7 @@
 	    j = i + 2;
 	    if (j == tmp.size() - 1) ++j;
 
-	    string dest = tmpdir;
+	    std::string dest = tmpdir;
 	    char buf[64];
 	    sprintf(buf, "/tmp%u_%u.", c, i / 2);
 	    dest += buf;
@@ -726,8 +726,8 @@
 }
 
 static void
-merge_docid_keyed(ChertTable *out, const vector<ChertTable*> & inputs,
-		  const vector<Xapian::docid> & offset)
+merge_docid_keyed(ChertTable *out, const std::vector<ChertTable*> & inputs,
+		  const std::vector<Xapian::docid> & offset)
 {
     for (size_t i = 0; i < inputs.size(); ++i) {
 	Xapian::docid off = offset[i];
@@ -738,7 +738,7 @@
 	ChertCursor cur(in);
 	cur.find_entry(string());
 
-	string key;
+	std::string key;
 	while (cur.next()) {
 	    // Adjust the key if this isn't the first database.
 	    if (off) {
@@ -746,7 +746,7 @@
 		const char * d = cur.current_key.data();
 		const char * e = d + cur.current_key.size();
 		if (!C_unpack_uint_preserving_sort(&d, e, &did)) {
-		    string msg = "Bad key in ";
+		    std::string msg = "Bad key in ";
 		    msg += inputs[i]->get_path();
 		    msg += "DB";
 		    throw Xapian::DatabaseCorruptError(msg);
@@ -774,8 +774,8 @@
 void
 ChertDatabase::compact(Xapian::Compactor * compactor,
 		       const char * destdir,
-		       const vector<Xapian::Database::Internal*> & sources,
-		       const vector<Xapian::docid> & offset,
+		       const std::vector<Xapian::Database::Internal*> & sources,
+		       const std::vector<Xapian::docid> & offset,
 		       size_t block_size,
 		       Xapian::Compactor::compaction_level compaction,
 		       unsigned flags,
@@ -831,14 +831,14 @@
 
     FlintLock lock(destdir);
     {
-	string explanation;
+	std::string explanation;
 	FlintLock::reason why = lock.lock(true, false, explanation);
 	if (why != FlintLock::SUCCESS) {
 	    lock.throw_databaselockerror(why, destdir, explanation);
 	}
     }
 
-    vector<ChertTable *> tabs;
+    std::vector<ChertTable *> tabs;
     tabs.reserve(tables_end - tables);
     for (const table_list * t = tables; t < tables_end; ++t) {
 	// The postlist table requires an N-way merge, adjusting the
@@ -849,7 +849,7 @@
 	if (compactor)
 	    compactor->set_status(t->name, string());
 
-	string dest = destdir;
+	std::string dest = destdir;
 	dest += '/';
 	dest += t->name;
 	dest += '.';
@@ -910,7 +910,7 @@
 	if (t->type == TERMLIST && inputs_present != sources.size()) {
 	    if (inputs_present != 0) {
 		if (compactor) {
-		    string m = str(inputs_present);
+		    std::string m = str(inputs_present);
 		    m += " of ";
 		    m += str(sources.size());
 		    m += " inputs present, so suppressing output";
@@ -978,7 +978,7 @@
 	    if (compactor)
 		compactor->set_status(t->name, "Done (couldn't stat all the DB files)");
 	} else {
-	    string status;
+	    std::string status;
 	    if (out_size == in_size) {
 		status = "Size unchanged (";
 	    } else {
diff -ur xapian-core-1.4.21/backends/chert/chert_cursor.cc xapian-core-1.4.21/backends/chert/chert_cursor.cc
--- xapian-core-1.4.21/backends/chert/chert_cursor.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_cursor.cc	2022-11-08 16:44:15.392461814 +0100
@@ -33,10 +33,10 @@
 
 #ifdef XAPIAN_DEBUG_LOG
 static string
-hex_display_encode(const string & input)
+hex_display_encode(const std::string & input)
 {
     const char * table = "0123456789abcdef";
-    string result;
+    std::string result;
     for (string::const_iterator i = input.begin(); i != input.end(); ++i) {
 	unsigned char val = *i;
 	result += "\\x";
@@ -192,7 +192,7 @@
 }
 
 bool
-ChertCursor::find_entry(const string &key)
+ChertCursor::find_entry(const std::string &key)
 {
     LOGCALL(DB, bool, "ChertCursor::find_entry", key);
     if (B->cursor_version != version) {
@@ -240,7 +240,7 @@
 }
 
 bool
-ChertCursor::find_entry_ge(const string &key)
+ChertCursor::find_entry_ge(const std::string &key)
 {
     LOGCALL(DB, bool, "ChertCursor::find_entry_ge", key);
     if (B->cursor_version != version) {
diff -ur xapian-core-1.4.21/backends/chert/chert_cursor.h xapian-core-1.4.21/backends/chert/chert_cursor.h
--- xapian-core-1.4.21/backends/chert/chert_cursor.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_cursor.h	2022-11-08 16:44:00.944513174 +0100
@@ -115,7 +115,7 @@
 	 *  e.g.
 	 *
 	 *    ChertCursor BC(&btree);
-	 *    string key;
+	 *    std::string key;
 	 *
 	 *    // Now do something to each key in the Btree
 	 *    BC.find_entry(string()); // must give result true
@@ -146,12 +146,12 @@
 
 	/** Current key pointed to by cursor.
 	 */
-	string current_key;
+	std::string current_key;
 
 	/** Current tag pointed to by cursor.  You must call read_tag to
 	 *  make this value available.
 	 */
-	string current_tag;
+	std::string current_tag;
 
 	/** Read the tag from the table and store it in current_tag.
 	 *
@@ -212,10 +212,10 @@
 	 *  @return true if the exact key was found in the table, false
 	 *          otherwise.
 	 */
-	bool find_entry(const string &key);
+	bool find_entry(const std::string &key);
 
 	/// Position the cursor on the highest entry with key < @a key.
-	void find_entry_lt(const string &key) {
+	void find_entry_lt(const std::string &key) {
 	    if (find_entry(key)) prev();
 	}
 
@@ -224,7 +224,7 @@
 	 *  @return true if the exact key was found in the table, false
 	 *          otherwise.
 	 */
-	bool find_entry_ge(const string &key);
+	bool find_entry_ge(const std::string &key);
 
 	/** Set the cursor to be off the end of the table.
 	 */
diff -ur xapian-core-1.4.21/backends/chert/chert_database.cc xapian-core-1.4.21/backends/chert/chert_database.cc
--- xapian-core-1.4.21/backends/chert/chert_database.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_database.cc	2022-11-08 16:44:15.396461799 +0100
@@ -78,7 +78,7 @@
 
 // The maximum safe term length is determined by the postlist.  There we
 // store the term using pack_string_preserving_sort() which takes the
-// length of the string plus an extra byte (assuming the string doesn't
+// length of the std::string plus an extra byte (assuming the std::string doesn't
 // contain any zero bytes), followed by the docid with encoded with
 // C_pack_uint_preserving_sort() which takes up to 5 bytes.
 //
@@ -102,7 +102,7 @@
  * determining the current and next revision numbers, and stores handles
  * to the tables.
  */
-ChertDatabase::ChertDatabase(const string &chert_dir, int flags,
+ChertDatabase::ChertDatabase(const std::string &chert_dir, int flags,
 			     unsigned int block_size)
 	: db_dir(chert_dir),
 	  readonly(flags == Xapian::DB_READONLY_),
@@ -335,13 +335,13 @@
 }
 
 void
-ChertDatabase::get_changeset_revisions(const string & path,
+ChertDatabase::get_changeset_revisions(const std::string & path,
 				       chert_revision_number_t * startrev,
 				       chert_revision_number_t * endrev) const
 {
     FD changes_fd(posixy_open(path.c_str(), O_RDONLY | O_CLOEXEC));
     if (changes_fd < 0) {
-	string message = string("Couldn't open changeset ")
+	std::string message = string("Couldn't open changeset ")
 		+ path + " to read";
 	throw Xapian::DatabaseError(message, errno);
     }
@@ -353,7 +353,7 @@
 	throw Xapian::DatabaseError("Changeset too short at " + path);
     if (memcmp(start, CHANGES_MAGIC_STRING,
 	       CONST_STRLEN(CHANGES_MAGIC_STRING)) != 0) {
-	string message = string("Changeset at ")
+	std::string message = string("Changeset at ")
 		+ path + " does not contain valid magic string";
 	throw Xapian::DatabaseError(message);
     }
@@ -391,7 +391,7 @@
     record_table.flush_db();
 
     int changes_fd = -1;
-    string changes_name;
+    std::string changes_name;
 
     const char *p = getenv("XAPIAN_MAX_CHANGESETS");
     if (p) {
@@ -413,7 +413,7 @@
     try {
 	FD closefd(changes_fd);
 	if (changes_fd >= 0) {
-	    string buf;
+	    std::string buf;
 	    chert_revision_number_t old_revision = get_revision_number();
 	    buf += CHANGES_MAGIC_STRING;
 	    pack_uint(buf, CHANGES_VERSION);
@@ -446,7 +446,7 @@
 	synonym_table.commit(new_revision, changes_fd);
 	spelling_table.commit(new_revision, changes_fd);
 
-	string changes_tail; // Data to be appended to the changes file
+	std::string changes_tail; // Data to be appended to the changes file
 	if (changes_fd >= 0) {
 	    changes_tail += '\0';
 	    pack_uint(changes_tail, new_revision);
@@ -481,7 +481,7 @@
 {
     Xapian::TermIterator t;
     for (t = query.get_unique_terms_begin(); t != Xapian::TermIterator(); ++t) {
-	const string & term = *t;
+	const std::string & term = *t;
 	if (!postlist_table.readahead_key(ChertPostListTable::make_key(term)))
 	    break;
     }
@@ -512,12 +512,12 @@
 ChertDatabase::get_database_write_lock(int flags, bool creating)
 {
     LOGCALL_VOID(DB, "ChertDatabase::get_database_write_lock", flags|creating);
-    string explanation;
+    std::string explanation;
     bool retry = flags & Xapian::DB_RETRY_LOCK;
     FlintLock::reason why = lock.lock(true, retry, explanation);
     if (why != FlintLock::SUCCESS) {
 	if (why == FlintLock::UNKNOWN && !creating && !database_exists()) {
-	    string msg("No chert database found at path '");
+	    std::string msg("No chert database found at path '");
 	    msg += db_dir;
 	    msg += '\'';
 	    throw Xapian::DatabaseNotFoundError(msg);
@@ -532,8 +532,8 @@
     LOGCALL_VOID(DB, "ChertDatabase::send_whole_database", conn | end_time);
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     // Send the current revision number in the header.
-    string buf;
-    string uuid = get_uuid();
+    std::string buf;
+    std::string uuid = get_uuid();
     buf += encode_length(uuid.size());
     buf += uuid;
     pack_uint(buf, get_revision_number());
@@ -549,10 +549,10 @@
 	"\x0b""position.DB""\x0e""position.baseA\x0e""position.baseB"
 	"\x0b""postlist.DB""\x0e""postlist.baseA\x0e""postlist.baseB"
 	"\x08""iamchert";
-    string filepath = db_dir;
+    std::string filepath = db_dir;
     filepath += '/';
     for (const char * p = filenames; *p; p += *p + 1) {
-	string leaf(p + 1, size_t(static_cast<unsigned char>(*p)));
+	std::string leaf(p + 1, size_t(static_cast<unsigned char>(*p)));
 	filepath.replace(db_dir.size() + 1, string::npos, leaf);
 	FD fd(posixy_open(filepath.c_str(), O_RDONLY | O_CLOEXEC));
 	if (fd >= 0) {
@@ -568,7 +568,7 @@
 
 void
 ChertDatabase::write_changesets_to_fd(int fd,
-				      const string & revision,
+				      const std::string & revision,
 				      bool need_whole_db,
 				      ReplicationInfo * info)
 {
@@ -576,7 +576,7 @@
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     int whole_db_copies_left = MAX_DB_COPIES_PER_CONVERSATION;
     chert_revision_number_t start_rev_num = 0;
-    string start_uuid = get_uuid();
+    std::string start_uuid = get_uuid();
 
     chert_revision_number_t needed_rev_num = 0;
 
@@ -623,7 +623,7 @@
 		// The update must proceed to that revision number before the
 		// copy is safe to make live.
 
-		string buf;
+		std::string buf;
 		needed_rev_num = get_revision_number();
 		pack_uint(buf, needed_rev_num);
 		conn.send_message(REPL_REPLY_DB_FOOTER, buf, 0.0);
@@ -638,7 +638,7 @@
 		// because the next message is going to be the start of a new
 		// database transfer.
 
-		string buf;
+		std::string buf;
 		pack_uint(buf, start_rev_num + 1);
 		conn.send_message(REPL_REPLY_DB_FOOTER, buf, 0.0);
 		need_whole_db = true;
@@ -657,7 +657,7 @@
 	    }
 
 	    // Look for the changeset for revision start_rev_num.
-	    string changes_name = db_dir + "/changes" + str(start_rev_num);
+	    std::string changes_name = db_dir + "/changes" + str(start_rev_num);
 	    FD fd_changes(posixy_open(changes_name.c_str(), O_RDONLY | O_CLOEXEC));
 	    if (fd_changes >= 0) {
 		// Send it, and also update start_rev_num to the new value
@@ -813,7 +813,7 @@
 }
 
 void
-ChertDatabase::get_freqs(const string & term,
+ChertDatabase::get_freqs(const std::string & term,
 			 Xapian::doccount * termfreq_ptr,
 			 Xapian::termcount * collfreq_ptr) const
 {
@@ -856,7 +856,7 @@
 }
 
 Xapian::termcount
-ChertDatabase::get_wdf_upper_bound(const string & term) const
+ChertDatabase::get_wdf_upper_bound(const std::string & term) const
 {
     Xapian::termcount cf;
     get_freqs(term, NULL, &cf);
@@ -864,7 +864,7 @@
 }
 
 bool
-ChertDatabase::term_exists(const string & term) const
+ChertDatabase::term_exists(const std::string & term) const
 {
     LOGCALL(DB, bool, "ChertDatabase::term_exists", term);
     Assert(!term.empty());
@@ -928,7 +928,7 @@
 }
 
 PositionList *
-ChertDatabase::open_position_list(Xapian::docid did, const string & term) const
+ChertDatabase::open_position_list(Xapian::docid did, const std::string & term) const
 {
     Assert(did != 0);
 
@@ -943,7 +943,7 @@
 }
 
 TermList *
-ChertDatabase::open_allterms(const string & prefix) const
+ChertDatabase::open_allterms(const std::string & prefix) const
 {
     LOGCALL(DB, TermList *, "ChertDatabase::open_allterms", NO_ARGS);
     RETURN(new ChertAllTermsList(intrusive_ptr<const ChertDatabase>(this),
@@ -951,7 +951,7 @@
 }
 
 TermList *
-ChertDatabase::open_spelling_termlist(const string & word) const
+ChertDatabase::open_spelling_termlist(const std::string & word) const
 {
     return spelling_table.open_termlist(word);
 }
@@ -966,19 +966,19 @@
 }
 
 Xapian::doccount
-ChertDatabase::get_spelling_frequency(const string & word) const
+ChertDatabase::get_spelling_frequency(const std::string & word) const
 {
     return spelling_table.get_word_frequency(word);
 }
 
 TermList *
-ChertDatabase::open_synonym_termlist(const string & term) const
+ChertDatabase::open_synonym_termlist(const std::string & term) const
 {
     return synonym_table.open_termlist(term);
 }
 
 TermList *
-ChertDatabase::open_synonym_keylist(const string & prefix) const
+ChertDatabase::open_synonym_keylist(const std::string & prefix) const
 {
     ChertCursor * cursor = synonym_table.cursor_get();
     if (!cursor) return NULL;
@@ -987,12 +987,12 @@
 }
 
 string
-ChertDatabase::get_metadata(const string & key) const
+ChertDatabase::get_metadata(const std::string & key) const
 {
     LOGCALL(DB, string, "ChertDatabase::get_metadata", key);
-    string btree_key("\x00\xc0", 2);
+    std::string btree_key("\x00\xc0", 2);
     btree_key += key;
-    string tag;
+    std::string tag;
     (void)postlist_table.get_exact_entry(btree_key, tag);
     RETURN(tag);
 }
@@ -1011,7 +1011,7 @@
 ChertDatabase::get_revision_info() const
 {
     LOGCALL(DB, string, "ChertDatabase::get_revision_info", NO_ARGS);
-    string buf;
+    std::string buf;
     pack_uint(buf, get_revision_number());
     RETURN(buf);
 }
@@ -1060,7 +1060,7 @@
 
 ///////////////////////////////////////////////////////////////////////////
 
-ChertWritableDatabase::ChertWritableDatabase(const string &dir, int action,
+ChertWritableDatabase::ChertWritableDatabase(const std::string &dir, int action,
 					       int block_size)
 	: ChertDatabase(dir, action, block_size),
 	  freq_deltas(),
@@ -1145,11 +1145,11 @@
 }
 
 void
-ChertWritableDatabase::add_freq_delta(const string & tname,
+ChertWritableDatabase::add_freq_delta(const std::string & tname,
 				      Xapian::termcount_diff tf_delta,
 				      Xapian::termcount_diff cf_delta)
 {
-    map<string, pair<termcount_diff, termcount_diff> >::iterator i;
+    std::map<string, std::pair<termcount_diff, termcount_diff> >::iterator i;
     i = freq_deltas.find(tname);
     if (i == freq_deltas.end()) {
 	freq_deltas.insert(make_pair(tname, make_pair(tf_delta, cf_delta)));
@@ -1161,14 +1161,14 @@
 
 void
 ChertWritableDatabase::insert_mod_plist(Xapian::docid did,
-					const string & tname,
+					const std::string & tname,
 					Xapian::termcount wdf)
 {
     // Find or make the appropriate entry in mod_plists.
-    map<string, map<docid, pair<char, termcount> > >::iterator j;
+    std::map<string, std::map<docid, std::pair<char, termcount> > >::iterator j;
     j = mod_plists.find(tname);
     if (j == mod_plists.end()) {
-	map<docid, pair<char, termcount> > m;
+	std::map<docid, std::pair<char, termcount> > m;
 	j = mod_plists.insert(make_pair(tname, m)).first;
     }
     j->second[did] = make_pair('A', wdf);
@@ -1176,19 +1176,19 @@
 
 void
 ChertWritableDatabase::update_mod_plist(Xapian::docid did,
-					const string & tname,
+					const std::string & tname,
 					char type,
 					Xapian::termcount wdf)
 {
     // Find or make the appropriate entry in mod_plists.
-    map<string, map<docid, pair<char, termcount> > >::iterator j;
+    std::map<string, std::map<docid, std::pair<char, termcount> > >::iterator j;
     j = mod_plists.find(tname);
     if (j == mod_plists.end()) {
-	map<docid, pair<char, termcount> > m;
+	std::map<docid, std::pair<char, termcount> > m;
 	j = mod_plists.insert(make_pair(tname, m)).first;
     }
 
-    map<docid, pair<char, termcount> >::iterator k;
+    std::map<docid, std::pair<char, termcount> >::iterator k;
     k = j->second.find(did);
     if (k == j->second.end()) {
 	j->second.insert(make_pair(did, make_pair(type, wdf)));
@@ -1235,7 +1235,7 @@
 		new_doclen += wdf;
 		stats.check_wdf(wdf);
 
-		string tname = *term;
+		std::string tname = *term;
 		if (tname.size() > MAX_SAFE_TERM_LENGTH)
 		    throw Xapian::InvalidArgumentError("Term too long (> " STRINGIZE(MAX_SAFE_TERM_LENGTH) "): " + tname);
 		add_freq_delta(tname, 1, wdf);
@@ -1306,7 +1306,7 @@
 
 	termlist.next();
 	while (!termlist.at_end()) {
-	    string tname = termlist.get_termname();
+	    std::string tname = termlist.get_termname();
 	    position_table.delete_positionlist(did, tname);
 	    termcount wdf = termlist.get_wdf();
 
@@ -1394,7 +1394,7 @@
 	    stats.delete_document(old_doclen);
 	    chert_doclen_t new_doclen = old_doclen;
 
-	    string old_tname, new_tname;
+	    std::string old_tname, new_tname;
 
 	    termlist.next();
 	    while (!termlist.at_end() || term != document.termlist_end()) {
@@ -1521,7 +1521,7 @@
 ChertWritableDatabase::get_doclength(Xapian::docid did) const
 {
     LOGCALL(DB, Xapian::termcount, "ChertWritableDatabase::get_doclength", did);
-    map<docid, termcount>::const_iterator i = doclens.find(did);
+    std::map<docid, termcount>::const_iterator i = doclens.find(did);
     if (i != doclens.end()) {
 	Xapian::termcount doclen = i->second;
 	if (doclen == static_cast<Xapian::termcount>(-1)) {
@@ -1542,7 +1542,7 @@
     // get_unique_terms() really ought to only count terms with wdf > 0, but
     // that's expensive to calculate on demand, so for now let's just ensure
     // unique_terms <= doclen.
-    map<docid, termcount>::const_iterator i = doclens.find(did);
+    std::map<docid, termcount>::const_iterator i = doclens.find(did);
     if (i != doclens.end()) {
 	Xapian::termcount doclen = i->second;
 	if (doclen == static_cast<Xapian::termcount>(-1)) {
@@ -1556,14 +1556,14 @@
 }
 
 void
-ChertWritableDatabase::get_freqs(const string & term,
+ChertWritableDatabase::get_freqs(const std::string & term,
 				 Xapian::doccount * termfreq_ptr,
 				 Xapian::termcount * collfreq_ptr) const
 {
     LOGCALL_VOID(DB, "ChertWritableDatabase::get_freqs", term | termfreq_ptr | collfreq_ptr);
     Assert(!term.empty());
     ChertDatabase::get_freqs(term, termfreq_ptr, collfreq_ptr);
-    map<string, pair<termcount_diff, termcount_diff> >::const_iterator i;
+    std::map<string, std::pair<termcount_diff, termcount_diff> >::const_iterator i;
     i = freq_deltas.find(term);
     if (i != freq_deltas.end()) {
 	if (termfreq_ptr)
@@ -1577,7 +1577,7 @@
 ChertWritableDatabase::get_value_freq(Xapian::valueno slot) const
 {
     LOGCALL(DB, Xapian::doccount, "ChertWritableDatabase::get_value_freq", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.freq);
     RETURN(ChertDatabase::get_value_freq(slot));
@@ -1587,7 +1587,7 @@
 ChertWritableDatabase::get_value_lower_bound(Xapian::valueno slot) const
 {
     LOGCALL(DB, std::string, "ChertWritableDatabase::get_value_lower_bound", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.lower_bound);
     RETURN(ChertDatabase::get_value_lower_bound(slot));
@@ -1597,14 +1597,14 @@
 ChertWritableDatabase::get_value_upper_bound(Xapian::valueno slot) const
 {
     LOGCALL(DB, std::string, "ChertWritableDatabase::get_value_upper_bound", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.upper_bound);
     RETURN(ChertDatabase::get_value_upper_bound(slot));
 }
 
 bool
-ChertWritableDatabase::term_exists(const string & tname) const
+ChertWritableDatabase::term_exists(const std::string & tname) const
 {
     LOGCALL(DB, bool, "ChertWritableDatabase::term_exists", tname);
     Xapian::doccount tf;
@@ -1629,7 +1629,7 @@
 	RETURN(new ChertAllDocsModifiedPostList(ptrtothis, doccount, doclens));
     }
 
-    map<string, map<docid, pair<char, termcount> > >::const_iterator j;
+    std::map<string, std::map<docid, std::pair<char, termcount> > >::const_iterator j;
     j = mod_plists.find(tname);
     if (j != mod_plists.end()) {
 	// We've got buffered changes to this term's postlist, so we need to
@@ -1652,7 +1652,7 @@
 }
 
 TermList *
-ChertWritableDatabase::open_allterms(const string & prefix) const
+ChertWritableDatabase::open_allterms(const std::string & prefix) const
 {
     LOGCALL(DB, TermList *, "ChertWritableDatabase::open_allterms", NO_ARGS);
     // If there are changes, terms may have been added or removed, and so we
@@ -1675,14 +1675,14 @@
 }
 
 void
-ChertWritableDatabase::add_spelling(const string & word,
+ChertWritableDatabase::add_spelling(const std::string & word,
 				    Xapian::termcount freqinc) const
 {
     spelling_table.add_word(word, freqinc);
 }
 
 void
-ChertWritableDatabase::remove_spelling(const string & word,
+ChertWritableDatabase::remove_spelling(const std::string & word,
 				       Xapian::termcount freqdec) const
 {
     spelling_table.remove_word(word, freqdec);
@@ -1696,37 +1696,37 @@
 }
 
 TermList *
-ChertWritableDatabase::open_synonym_keylist(const string & prefix) const
+ChertWritableDatabase::open_synonym_keylist(const std::string & prefix) const
 {
     synonym_table.merge_changes();
     return ChertDatabase::open_synonym_keylist(prefix);
 }
 
 void
-ChertWritableDatabase::add_synonym(const string & term,
-				   const string & synonym) const
+ChertWritableDatabase::add_synonym(const std::string & term,
+				   const std::string & synonym) const
 {
     synonym_table.add_synonym(term, synonym);
 }
 
 void
-ChertWritableDatabase::remove_synonym(const string & term,
-				      const string & synonym) const
+ChertWritableDatabase::remove_synonym(const std::string & term,
+				      const std::string & synonym) const
 {
     synonym_table.remove_synonym(term, synonym);
 }
 
 void
-ChertWritableDatabase::clear_synonyms(const string & term) const
+ChertWritableDatabase::clear_synonyms(const std::string & term) const
 {
     synonym_table.clear_synonyms(term);
 }
 
 void
-ChertWritableDatabase::set_metadata(const string & key, const string & value)
+ChertWritableDatabase::set_metadata(const std::string & key, const std::string & value)
 {
     LOGCALL_VOID(DB, "ChertWritableDatabase::set_metadata", key | value);
-    string btree_key("\x00\xc0", 2);
+    std::string btree_key("\x00\xc0", 2);
     btree_key += key;
     if (value.empty()) {
 	postlist_table.del(btree_key);
diff -ur xapian-core-1.4.21/backends/chert/chert_database.h xapian-core-1.4.21/backends/chert/chert_database.h
--- xapian-core-1.4.21/backends/chert/chert_database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_database.h	2022-11-08 16:44:00.952513146 +0100
@@ -192,7 +192,7 @@
 
 	/** Called if a modifications fail.
 	 *
-	 *  @param msg is a string description of the exception that was
+	 *  @param msg is a std::string description of the exception that was
 	 *  raised when the modifications failed.
 	 */
 	void modifications_failed(chert_revision_number_t old_revision,
@@ -219,7 +219,7 @@
 
 	/** Get the revision stored in a changeset.
 	 */
-	void get_changeset_revisions(const string & path,
+	void get_changeset_revisions(const std::string & path,
 				     chert_revision_number_t * startrev,
 				     chert_revision_number_t * endrev) const;
     public:
@@ -242,7 +242,7 @@
 	 *                    correct value, when the database is being
 	 *                    created.
 	 */
-	ChertDatabase(const string &db_dir_, int action = Xapian::DB_READONLY_,
+	ChertDatabase(const std::string &db_dir_, int action = Xapian::DB_READONLY_,
 		      unsigned int block_size = 0u);
 
 	~ChertDatabase();
@@ -266,7 +266,7 @@
 	Xapian::totallength get_total_length() const;
 	Xapian::termcount get_doclength(Xapian::docid did) const;
 	Xapian::termcount get_unique_terms(Xapian::docid did) const;
-	void get_freqs(const string & term,
+	void get_freqs(const std::string & term,
 		       Xapian::doccount * termfreq_ptr,
 		       Xapian::termcount * collfreq_ptr) const;
 	Xapian::doccount get_value_freq(Xapian::valueno slot) const;
@@ -274,33 +274,33 @@
 	std::string get_value_upper_bound(Xapian::valueno slot) const;
 	Xapian::termcount get_doclength_lower_bound() const;
 	Xapian::termcount get_doclength_upper_bound() const;
-	Xapian::termcount get_wdf_upper_bound(const string & term) const;
-	bool term_exists(const string & tname) const;
+	Xapian::termcount get_wdf_upper_bound(const std::string & term) const;
+	bool term_exists(const std::string & tname) const;
 	bool has_positions() const;
 
-	LeafPostList * open_post_list(const string & tname) const;
+	LeafPostList * open_post_list(const std::string & tname) const;
 	ValueList * open_value_list(Xapian::valueno slot) const;
 	Xapian::Document::Internal * open_document(Xapian::docid did, bool lazy) const;
 
-	PositionList * open_position_list(Xapian::docid did, const string & term) const;
+	PositionList * open_position_list(Xapian::docid did, const std::string & term) const;
 	TermList * open_term_list(Xapian::docid did) const;
-	TermList * open_allterms(const string & prefix) const;
+	TermList * open_allterms(const std::string & prefix) const;
 
-	TermList * open_spelling_termlist(const string & word) const;
+	TermList * open_spelling_termlist(const std::string & word) const;
 	TermList * open_spelling_wordlist() const;
-	Xapian::doccount get_spelling_frequency(const string & word) const;
+	Xapian::doccount get_spelling_frequency(const std::string & word) const;
 
-	TermList * open_synonym_termlist(const string & term) const;
-	TermList * open_synonym_keylist(const string & prefix) const;
+	TermList * open_synonym_termlist(const std::string & term) const;
+	TermList * open_synonym_keylist(const std::string & prefix) const;
 
-	string get_metadata(const string & key) const;
+	std::string get_metadata(const std::string & key) const;
 	TermList * open_metadata_keylist(const std::string &prefix) const;
 	void write_changesets_to_fd(int fd,
-				    const string & start_revision,
+				    const std::string & start_revision,
 				    bool need_whole_db,
 				    Xapian::ReplicationInfo * info);
-	string get_revision_info() const;
-	string get_uuid() const;
+	std::string get_revision_info() const;
+	std::string get_uuid() const;
 
 	void request_document(Xapian::docid /*did*/) const;
 	void readahead_for_query(const Xapian::Query &query);
@@ -335,17 +335,17 @@
  */
 class ChertWritableDatabase : public ChertDatabase {
 	/** Unflushed changes to term frequencies and collection frequencies. */
-	mutable map<string, pair<Xapian::termcount_diff, Xapian::termcount_diff> >
+	mutable std::map<string, std::pair<Xapian::termcount_diff, Xapian::termcount_diff> >
 		freq_deltas;
 
 	/** Document lengths of new and modified documents which haven't been flushed yet. */
-	mutable map<Xapian::docid, Xapian::termcount> doclens;
+	mutable std::map<Xapian::docid, Xapian::termcount> doclens;
 
 	/// Modifications to posting lists.
-	mutable map<string, map<Xapian::docid,
-				pair<char, Xapian::termcount> > > mod_plists;
+	mutable std::map<string, std::map<Xapian::docid,
+				std::pair<char, Xapian::termcount> > > mod_plists;
 
-	mutable map<Xapian::valueno, ValueStats> value_stats;
+	mutable std::map<Xapian::valueno, ValueStats> value_stats;
 
 	/** The number of documents added, deleted, or replaced since the last
 	 *  flush.
@@ -388,7 +388,7 @@
 	 *  @param tf_delta The change in the term frequency delta.
 	 *  @param cf_delta The change in the collection frequency delta.
 	 */
-	void add_freq_delta(const string & tname,
+	void add_freq_delta(const std::string & tname,
 			    Xapian::termcount_diff tf_delta,
 			    Xapian::termcount_diff cf_delta);
 
@@ -399,7 +399,7 @@
 	 *  @param wdf The new wdf value to store.
 	 */
 	void insert_mod_plist(Xapian::docid did,
-			      const string & tname,
+			      const std::string & tname,
 			      Xapian::termcount wdf);
 
 	/** Update the stored modifications to the postlists.
@@ -414,7 +414,7 @@
 	 *  cases, the stored type is simply the value supplied.
 	 */
 	void update_mod_plist(Xapian::docid did,
-			      const string & tname,
+			      const std::string & tname,
 			      char type,
 			      Xapian::termcount wdf);
 
@@ -458,7 +458,7 @@
 	 *
 	 *  @param dir directory holding chert tables
 	 */
-	ChertWritableDatabase(const string &dir, int action, int block_size);
+	ChertWritableDatabase(const std::string &dir, int action, int block_size);
 
 	~ChertWritableDatabase();
 
@@ -466,28 +466,28 @@
 	//@{
 	Xapian::termcount get_doclength(Xapian::docid did) const;
 	Xapian::termcount get_unique_terms(Xapian::docid did) const;
-	void get_freqs(const string & term,
+	void get_freqs(const std::string & term,
 		       Xapian::doccount * termfreq_ptr,
 		       Xapian::termcount * collfreq_ptr) const;
 	Xapian::doccount get_value_freq(Xapian::valueno slot) const;
 	std::string get_value_lower_bound(Xapian::valueno slot) const;
 	std::string get_value_upper_bound(Xapian::valueno slot) const;
-	bool term_exists(const string & tname) const;
+	bool term_exists(const std::string & tname) const;
 
-	LeafPostList * open_post_list(const string & tname) const;
+	LeafPostList * open_post_list(const std::string & tname) const;
 	ValueList * open_value_list(Xapian::valueno slot) const;
-	TermList * open_allterms(const string & prefix) const;
+	TermList * open_allterms(const std::string & prefix) const;
 
-	void add_spelling(const string & word, Xapian::termcount freqinc) const;
-	void remove_spelling(const string & word, Xapian::termcount freqdec) const;
+	void add_spelling(const std::string & word, Xapian::termcount freqinc) const;
+	void remove_spelling(const std::string & word, Xapian::termcount freqdec) const;
 	TermList * open_spelling_wordlist() const;
 
-	TermList * open_synonym_keylist(const string & prefix) const;
-	void add_synonym(const string & word, const string & synonym) const;
-	void remove_synonym(const string & word, const string & synonym) const;
-	void clear_synonyms(const string & word) const;
+	TermList * open_synonym_keylist(const std::string & prefix) const;
+	void add_synonym(const std::string & word, const std::string & synonym) const;
+	void remove_synonym(const std::string & word, const std::string & synonym) const;
+	void clear_synonyms(const std::string & word) const;
 
-	void set_metadata(const string & key, const string & value);
+	void set_metadata(const std::string & key, const std::string & value);
 	void invalidate_doc_object(Xapian::Document::Internal * obj) const;
 	//@}
 
diff -ur xapian-core-1.4.21/backends/chert/chert_databasereplicator.cc xapian-core-1.4.21/backends/chert/chert_databasereplicator.cc
--- xapian-core-1.4.21/backends/chert/chert_databasereplicator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_databasereplicator.cc	2022-11-08 16:44:15.392461814 +0100
@@ -58,7 +58,7 @@
 using namespace std;
 using namespace Xapian;
 
-ChertDatabaseReplicator::ChertDatabaseReplicator(const string & db_dir_)
+ChertDatabaseReplicator::ChertDatabaseReplicator(const std::string & db_dir_)
 	: db_dir(db_dir_),
 	  max_changesets(0)
 {
@@ -68,8 +68,8 @@
 }
 
 bool
-ChertDatabaseReplicator::check_revision_at_least(const string & rev,
-						 const string & target) const
+ChertDatabaseReplicator::check_revision_at_least(const std::string & rev,
+						 const std::string & target) const
 {
     LOGCALL(DB, bool, "ChertDatabaseReplicator::check_revision_at_least", rev | target);
 
@@ -79,21 +79,21 @@
     const char * ptr = rev.data();
     const char * end = ptr + rev.size();
     if (!unpack_uint(&ptr, end, &rev_val)) {
-	throw NetworkError("Invalid revision string supplied to check_revision_at_least");
+	throw NetworkError("Invalid revision std::string supplied to check_revision_at_least");
     }
 
     ptr = target.data();
     end = ptr + target.size();
     if (!unpack_uint(&ptr, end, &target_val)) {
-	throw NetworkError("Invalid revision string supplied to check_revision_at_least");
+	throw NetworkError("Invalid revision std::string supplied to check_revision_at_least");
     }
 
     RETURN(rev_val >= target_val);
 }
 
 void
-ChertDatabaseReplicator::process_changeset_chunk_base(const string & tablename,
-						      string & buf,
+ChertDatabaseReplicator::process_changeset_chunk_base(const std::string & tablename,
+						      std::string & buf,
 						      RemoteConnection & conn,
 						      double end_time,
 						      int changes_fd) const
@@ -125,11 +125,11 @@
     }
 
     // Write base_size bytes from start of buf to base file for tablename
-    string tmp_path = db_dir + "/" + tablename + "tmp";
-    string base_path = db_dir + "/" + tablename + ".base" + letter;
+    std::string tmp_path = db_dir + "/" + tablename + "tmp";
+    std::string base_path = db_dir + "/" + tablename + ".base" + letter;
     int fd = posixy_open(tmp_path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0666);
     if (fd == -1) {
-	string msg = "Failed to open ";
+	std::string msg = "Failed to open ";
 	msg += tmp_path;
 	throw DatabaseError(msg, errno);
     }
@@ -144,7 +144,7 @@
     write_and_clear_changes(changes_fd, buf, base_size);
 
     if (!io_tmp_rename(tmp_path, base_path)) {
-	string msg("Couldn't update base file ");
+	std::string msg("Couldn't update base file ");
 	msg += tablename;
 	msg += ".base";
 	msg += letter;
@@ -153,8 +153,8 @@
 }
 
 void
-ChertDatabaseReplicator::process_changeset_chunk_blocks(const string & tablename,
-							string & buf,
+ChertDatabaseReplicator::process_changeset_chunk_blocks(const std::string & tablename,
+							std::string & buf,
 							RemoteConnection & conn,
 							double end_time,
 							int changes_fd) const
@@ -167,10 +167,10 @@
 	throw NetworkError("Invalid blocksize in changeset");
     write_and_clear_changes(changes_fd, buf, ptr - buf.data());
 
-    string db_path = db_dir + "/" + tablename + ".DB";
+    std::string db_path = db_dir + "/" + tablename + ".DB";
     int fd = posixy_open(db_path.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0666);
     if (fd == -1) {
-	string msg = "Failed to open ";
+	std::string msg = "Failed to open ";
 	msg += db_path;
 	throw DatabaseError(msg, errno);
     }
@@ -216,7 +216,7 @@
 
     // Lock the database to perform modifications.
     FlintLock lock(db_dir);
-    string explanation;
+    std::string explanation;
     FlintLock::reason why = lock.lock(true, false, explanation);
     if (why != FlintLock::SUCCESS) {
 	lock.throw_databaselockerror(why, db_dir, explanation);
@@ -227,7 +227,7 @@
 	throw_connection_closed_unexpectedly();
     AssertEq(type, REPL_REPLY_CHANGESET);
 
-    string buf;
+    std::string buf;
     // Read enough to be certain that we've got the header part of the
     // changeset.
 
@@ -262,7 +262,7 @@
 	throw NetworkError("Unexpected end of changeset (1)");
 
     FD changes_fd;
-    string changes_name;
+    std::string changes_name;
     if (max_changesets > 0) {
 	changes_fd = create_changeset_file(db_dir, "changes" + str(startrev),
 					   changes_name);
@@ -305,7 +305,7 @@
 	    break;
 
 	// Get the tablename.
-	string tablename;
+	std::string tablename;
 	if (!unpack_string(&ptr, end, tablename))
 	    throw NetworkError("Unexpected end of changeset (3)");
 	if (tablename.empty())
diff -ur xapian-core-1.4.21/backends/chert/chert_dbcheck.cc xapian-core-1.4.21/backends/chert/chert_dbcheck.cc
--- xapian-core-1.4.21/backends/chert/chert_dbcheck.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_dbcheck.cc	2022-11-08 16:44:15.400461785 +0100
@@ -44,7 +44,7 @@
 using namespace std;
 
 static inline bool
-is_user_metadata_key(const string & key)
+is_user_metadata_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xc0';
 }
@@ -58,11 +58,11 @@
 size_t
 check_chert_table(const char * tablename, const string& dir,
 		  chert_revision_number_t * rev_ptr, int opts,
-		  vector<Xapian::termcount> & doclens,
+		  std::vector<Xapian::termcount> & doclens,
 		  Xapian::doccount doccount, Xapian::docid db_last_docid,
 		  ostream * out)
 {
-    string filename = dir;
+    std::string filename = dir;
     filename += '/';
     filename += tablename;
     filename += '.';
@@ -96,8 +96,8 @@
 
     if (strcmp(tablename, "postlist") == 0) {
 	// Now check the structure of each postlist in the table.
-	map<Xapian::valueno, VStats> valuestats;
-	string current_term;
+	std::map<Xapian::valueno, VStats> valuestats;
+	std::string current_term;
 	Xapian::docid lastdid = 0;
 	Xapian::termcount termfreq = 0, collfreq = 0;
 	Xapian::termcount tf = 0, cf = 0;
@@ -150,7 +150,7 @@
 
 	bool seen_doclen_initial_chunk = false;
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    if (is_user_metadata_key(key)) {
 		// User metadata can be anything, so we can't do any particular
@@ -393,7 +393,7 @@
 		end = p + cursor->current_tag.size();
 
 		while (true) {
-		    string value;
+		    std::string value;
 		    if (!unpack_string(&p, end, value)) {
 			if (out)
 			    *out << "Failed to unpack value from chunk" << endl;
@@ -458,7 +458,7 @@
 	    pos = key.data();
 	    end = pos + key.size();
 
-	    string term;
+	    std::string term;
 	    Xapian::docid did;
 	    if (!unpack_string_preserving_sort(&pos, end, term)) {
 		if (out)
@@ -636,7 +636,7 @@
 	    ++errors;
 	}
 
-	map<Xapian::valueno, VStats>::const_iterator i;
+	std::map<Xapian::valueno, VStats>::const_iterator i;
 	for (i = valuestats.begin(); i != valuestats.end(); ++i) {
 	    if (i->second.freq != i->second.freq_real) {
 		if (out)
@@ -658,7 +658,7 @@
 	// Now check the contents of the record table.  Any data is valid as
 	// the tag so we don't check the tags.
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
@@ -688,7 +688,7 @@
 	Xapian::doccount num_termlists = 0;
 	Xapian::doccount num_slotsused_entries = 0;
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
@@ -803,7 +803,7 @@
 	    }
 
 	    Xapian::termcount actual_doclen = 0, actual_termlist_size = 0;
-	    string current_tname;
+	    std::string current_tname;
 
 	    bool bad = false;
 	    while (pos != end) {
@@ -886,7 +886,7 @@
     } else if (strcmp(tablename, "position") == 0) {
 	// Now check the contents of the position table.
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
@@ -927,7 +927,7 @@
 
 	    cursor->read_tag();
 
-	    const string & data = cursor->current_tag;
+	    const std::string & data = cursor->current_tag;
 	    pos = data.data();
 	    end = pos + data.size();
 
diff -ur xapian-core-1.4.21/backends/chert/chert_dbstats.cc xapian-core-1.4.21/backends/chert/chert_dbstats.cc
--- xapian-core-1.4.21/backends/chert/chert_dbstats.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_dbstats.cc	2022-11-08 16:44:15.412461742 +0100
@@ -27,12 +27,12 @@
 using namespace std;
 
 /// The key in the postlist table which we use to store our encoded statistics.
-static const string DATABASE_STATS_KEY(1, '\0');
+static const std::string DATABASE_STATS_KEY(1, '\0');
 
 void
 ChertDatabaseStats::read(ChertPostListTable & postlist_table)
 {
-    string data;
+    std::string data;
     if (!postlist_table.get_exact_entry(DATABASE_STATS_KEY, data)) {
 	// If there's no entry yet, then all the values are zero.
 	total_doclen = 0;
@@ -67,7 +67,7 @@
 void
 ChertDatabaseStats::write(ChertPostListTable & postlist_table) const
 {
-    string data;
+    std::string data;
     pack_uint(data, last_docid);
     pack_uint(data, doclen_lbound);
     pack_uint(data, wdf_ubound);
diff -ur xapian-core-1.4.21/backends/chert/chert_document.cc xapian-core-1.4.21/backends/chert/chert_document.cc
--- xapian-core-1.4.21/backends/chert/chert_document.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_document.cc	2022-11-08 16:44:15.412461742 +0100
@@ -43,7 +43,7 @@
 /** Retrieve all value values from the database
  */
 void
-ChertDocument::do_get_all_values(map<Xapian::valueno, string> & values_) const
+ChertDocument::do_get_all_values(std::map<Xapian::valueno, string> & values_) const
 {
     LOGCALL_VOID(DB, "ChertDocument::do_get_all_values", values_);
     value_manager->get_all_values(values_, did);
diff -ur xapian-core-1.4.21/backends/chert/chert_document.h xapian-core-1.4.21/backends/chert/chert_document.h
--- xapian-core-1.4.21/backends/chert/chert_document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_document.h	2022-11-08 16:44:00.956513132 +0100
@@ -53,9 +53,9 @@
 
   public:
     /** Implementation of virtual methods @{ */
-    string do_get_value(Xapian::valueno slot) const;
-    void do_get_all_values(map<Xapian::valueno, string> & values_) const;
-    string do_get_data() const;
+    std::string do_get_value(Xapian::valueno slot) const;
+    void do_get_all_values(std::map<Xapian::valueno, string> & values_) const;
+    std::string do_get_data() const;
     /** @} */
 };
 
diff -ur xapian-core-1.4.21/backends/chert/chert_metadata.cc xapian-core-1.4.21/backends/chert/chert_metadata.cc
--- xapian-core-1.4.21/backends/chert/chert_metadata.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_metadata.cc	2022-11-08 16:44:15.384461842 +0100
@@ -33,7 +33,7 @@
 ChertMetadataTermList::ChertMetadataTermList(
 	intrusive_ptr<const Xapian::Database::Internal> database_,
 	ChertCursor * cursor_,
-	const string &prefix_)
+	const std::string &prefix_)
 	: database(database_), cursor(cursor_), prefix(string("\x00\xc0", 2) + prefix_)
 {
     LOGCALL_CTOR(DB, "ChertMetadataTermList", database_ | cursor_ | prefix_);
@@ -80,7 +80,7 @@
 }
 
 TermList *
-ChertMetadataTermList::skip_to(const string &key)
+ChertMetadataTermList::skip_to(const std::string &key)
 {
     LOGCALL(DB, TermList *, "ChertMetadataTermList::skip_to", key);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.cc xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.cc
--- xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.cc	2022-11-08 16:44:15.380461857 +0100
@@ -59,7 +59,7 @@
     if (it == mods.end()) return ChertPostList::get_docid();
     if (ChertPostList::at_end()) return it->first;
     Assert(it->second.first != 'D');
-    return min(it->first, ChertPostList::get_docid());
+    return std::min(it->first, ChertPostList::get_docid());
 }
 
 Xapian::termcount
diff -ur xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.h xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.h
--- xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_modifiedpostlist.h	2022-11-08 16:44:00.948513161 +0100
@@ -24,7 +24,7 @@
 #include <map>
 #include <string>
 
-using namespace std;
+using std::string;
 
 #include "chert_database.h"
 #include "chert_postlist.h"
@@ -32,8 +32,8 @@
 class ChertModifiedPostList : public ChertPostList {
     /// Modifications to apply to the ChertPostList.
     //@{
-    map<Xapian::docid, pair<char, Xapian::termcount> > mods;
-    map<Xapian::docid, pair<char, Xapian::termcount> >::const_iterator it;
+    std::map<Xapian::docid, std::pair<char, Xapian::termcount> > mods;
+    std::map<Xapian::docid, std::pair<char, Xapian::termcount> >::const_iterator it;
     //@}
 
     /// Pointer to PositionList returned from read_position_list to be deleted.
@@ -45,8 +45,8 @@
   public:
     /// Constructor.
     ChertModifiedPostList(Xapian::Internal::intrusive_ptr<const ChertDatabase> this_db_,
-			  const string & term_,
-			  const map<Xapian::docid, pair<char, Xapian::termcount> > & mods_)
+			  const std::string & term_,
+			  const std::map<Xapian::docid, std::pair<char, Xapian::termcount> > & mods_)
 	: ChertPostList(this_db_, term_, true),
 	  mods(mods_), it(mods.begin()), poslist(0)
     { }
diff -ur xapian-core-1.4.21/backends/chert/chert_positionlist.cc xapian-core-1.4.21/backends/chert/chert_positionlist.cc
--- xapian-core-1.4.21/backends/chert/chert_positionlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_positionlist.cc	2022-11-08 16:44:15.404461770 +0100
@@ -35,7 +35,7 @@
 
 void
 ChertPositionListTable::set_positionlist(Xapian::docid did,
-					 const string & tname,
+					 const std::string & tname,
 					 Xapian::PositionIterator pos,
 					 const Xapian::PositionIterator &pos_end,
 					 bool check_for_update)
@@ -44,11 +44,11 @@
     Assert(pos != pos_end);
 
     // FIXME: avoid the need for this copy!
-    vector<Xapian::termpos> poscopy(pos, pos_end);
+    std::vector<Xapian::termpos> poscopy(pos, pos_end);
 
-    string key = make_key(did, tname);
+    std::string key = make_key(did, tname);
 
-    string s;
+    std::string s;
     pack_uint(s, poscopy.back());
 
     if (poscopy.size() > 1) {
@@ -60,7 +60,7 @@
     }
 
     if (check_for_update) {
-	string old_tag;
+	std::string old_tag;
 	if (get_exact_entry(key, old_tag) && s == old_tag)
 	    return;
     }
@@ -69,11 +69,11 @@
 
 Xapian::termcount
 ChertPositionListTable::positionlist_count(Xapian::docid did,
-					   const string & term) const
+					   const std::string & term) const
 {
     LOGCALL(DB, Xapian::termcount, "ChertPositionListTable::positionlist_count", did | term);
 
-    string data;
+    std::string data;
     if (!get_exact_entry(make_key(did, term), data)) {
 	RETURN(0);
     }
@@ -100,13 +100,13 @@
 
 bool
 ChertPositionList::read_data(const ChertTable * table, Xapian::docid did,
-			     const string & tname)
+			     const std::string & tname)
 {
     LOGCALL(DB, bool, "ChertPositionList::read_data", table | did | tname);
 
     have_started = false;
 
-    string data;
+    std::string data;
     if (!table->get_exact_entry(ChertPositionListTable::make_key(did, tname), data)) {
 	// There's no positional information for this term.
 	size = 0;
diff -ur xapian-core-1.4.21/backends/chert/chert_positionlist.h xapian-core-1.4.21/backends/chert/chert_positionlist.h
--- xapian-core-1.4.21/backends/chert/chert_positionlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_positionlist.h	2022-11-08 16:44:00.944513174 +0100
@@ -31,12 +31,12 @@
 
 #include <string>
 
-using namespace std;
+using std::string;
 
 class ChertPositionListTable : public ChertLazyTable {
   public:
-    static string make_key(Xapian::docid did, const string & term) {
-	string key;
+    static std::string make_key(Xapian::docid did, const std::string & term) {
+	std::string key;
 	C_pack_uint_preserving_sort(key, did);
 	key += term;
 	return key;
@@ -50,7 +50,7 @@
      *  @param dbdir		The directory the chert database is stored in.
      *  @param readonly		true if we're opening read-only, else false.
      */
-    ChertPositionListTable(const string & dbdir, bool readonly)
+    ChertPositionListTable(const std::string & dbdir, bool readonly)
 	: ChertLazyTable("position", dbdir + "/position.", readonly,
 			 DONT_COMPRESS) { }
 
@@ -59,19 +59,19 @@
      *  @param check_for_update If true, check if the new list is the same as
      *				the existing list (if there is one).
      */
-    void set_positionlist(Xapian::docid did, const string & tname,
+    void set_positionlist(Xapian::docid did, const std::string & tname,
 			  Xapian::PositionIterator pos,
 			  const Xapian::PositionIterator &pos_end,
 			  bool check_for_update);
 
     /// Delete the position list for term tname in document did.
-    void delete_positionlist(Xapian::docid did, const string & tname) {
+    void delete_positionlist(Xapian::docid did, const std::string & tname) {
 	del(make_key(did, tname));
     }
 
     /// Return the number of entries in specified position list.
     Xapian::termcount positionlist_count(Xapian::docid did,
-					 const string & term) const;
+					 const std::string & term) const;
 };
 
 /** A position list in a chert database. */
@@ -103,7 +103,7 @@
 
     /// Construct and initialise with data.
     ChertPositionList(const ChertTable * table, Xapian::docid did,
-		      const string & tname) {
+		      const std::string & tname) {
 	(void)read_data(table, did, tname);
     }
 
@@ -112,7 +112,7 @@
      *  @return true if position data was read.
      */
     bool read_data(const ChertTable * table, Xapian::docid did,
-		   const string & tname);
+		   const std::string & tname);
 
     /// Returns size of position list.
     Xapian::termcount get_approx_size() const;
diff -ur xapian-core-1.4.21/backends/chert/chert_postlist.cc xapian-core-1.4.21/backends/chert/chert_postlist.cc
--- xapian-core-1.4.21/backends/chert/chert_postlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_postlist.cc	2022-11-08 16:44:15.404461770 +0100
@@ -34,12 +34,12 @@
 using Xapian::Internal::intrusive_ptr;
 
 void
-ChertPostListTable::get_freqs(const string & term,
+ChertPostListTable::get_freqs(const std::string & term,
 			      Xapian::doccount * termfreq_ptr,
 			      Xapian::termcount * collfreq_ptr) const
 {
-    string key = make_key(term);
-    string tag;
+    std::string key = make_key(term);
+    std::string tag;
     if (!get_exact_entry(key, tag)) {
 	if (termfreq_ptr)
 	    *termfreq_ptr = 0;
@@ -92,9 +92,9 @@
  */
 class Chert::PostlistChunkWriter {
     public:
-	PostlistChunkWriter(const string &orig_key_,
+	PostlistChunkWriter(const std::string &orig_key_,
 			    bool is_first_chunk_,
-			    const string &tname_,
+			    const std::string &tname_,
 			    bool is_last_chunk_);
 
 	/// Append an entry to this chunk.
@@ -103,7 +103,7 @@
 
 	/// Append a block of raw entries to this chunk.
 	void raw_append(Xapian::docid first_did_, Xapian::docid current_did_,
-			const string & s) {
+			const std::string & s) {
 	    Assert(!started);
 	    first_did = first_did_;
 	    current_did = current_did_;
@@ -120,8 +120,8 @@
 	void flush(ChertTable *table);
 
     private:
-	string orig_key;
-	string tname;
+	std::string orig_key;
+	std::string tname;
 	bool is_first_chunk;
 	bool is_last_chunk;
 	bool started;
@@ -129,7 +129,7 @@
 	Xapian::docid first_did;
 	Xapian::docid current_did;
 
-	string chunk;
+	std::string chunk;
 };
 
 using Chert::PostlistChunkWriter;
@@ -151,15 +151,15 @@
 }
 
 static inline bool get_tname_from_key(const char **src, const char *end,
-			       string &tname)
+			       std::string &tname)
 {
     return unpack_string_preserving_sort(src, end, tname);
 }
 
 static inline bool
-check_tname_in_key_lite(const char **keypos, const char *keyend, const string &tname)
+check_tname_in_key_lite(const char **keypos, const char *keyend, const std::string &tname)
 {
-    string tname_in_key;
+    std::string tname_in_key;
 
     if (keyend - *keypos >= 2 && (*keypos)[0] == '\0' && (*keypos)[1] == '\xe0') {
 	*keypos += 2;
@@ -174,7 +174,7 @@
 }
 
 static inline bool
-check_tname_in_key(const char **keypos, const char *keyend, const string &tname)
+check_tname_in_key(const char **keypos, const char *keyend, const std::string &tname)
 {
     if (*keypos == keyend) return false;
 
@@ -251,7 +251,7 @@
  *  entries in a postlist.
  */
 class Chert::PostlistChunkReader {
-    string data;
+    std::string data;
 
     const char *pos;
     const char *end;
@@ -265,9 +265,9 @@
     /** Initialise the postlist chunk reader.
      *
      *  @param first_did  First document id in this chunk.
-     *  @param data       The tag string with the header removed.
+     *  @param data       The tag std::string with the header removed.
      */
-    PostlistChunkReader(Xapian::docid first_did, const string & data_)
+    PostlistChunkReader(Xapian::docid first_did, const std::string & data_)
 	: data(data_), pos(data.data()), end(pos + data.length()), at_end(data.empty()), did(first_did)
     {
 	if (!at_end) read_wdf(&pos, end, &wdf);
@@ -302,9 +302,9 @@
     }
 }
 
-PostlistChunkWriter::PostlistChunkWriter(const string &orig_key_,
+PostlistChunkWriter::PostlistChunkWriter(const std::string &orig_key_,
 					 bool is_first_chunk_,
-					 const string &tname_,
+					 const std::string &tname_,
 					 bool is_last_chunk_)
 	: orig_key(orig_key_),
 	  tname(tname_), is_first_chunk(is_first_chunk_),
@@ -348,7 +348,7 @@
 			  Xapian::termcount collectionfreq,
 			  Xapian::docid new_did)
 {
-    string chunk;
+    std::string chunk;
     pack_uint(chunk, entries);
     pack_uint(chunk, collectionfreq);
     pack_uint(chunk, new_did - 1);
@@ -363,7 +363,7 @@
 		    Xapian::docid new_final_did)
 {
     Assert(new_final_did >= new_first_did);
-    string chunk;
+    std::string chunk;
     pack_bool(chunk, new_is_last_chunk);
     pack_uint(chunk, new_final_did - new_first_did);
     return chunk;
@@ -477,13 +477,13 @@
 		read_start_of_chunk(&tagpos, tagend, new_first_did,
 				    &new_is_last_chunk);
 
-	    string chunk_data(tagpos, tagend);
+	    std::string chunk_data(tagpos, tagend);
 
 	    // First remove the renamed tag
 	    table->del(cursor->current_key);
 
 	    // And now write it as the first chunk
-	    string tag;
+	    std::string tag;
 	    tag = make_start_of_first_chunk(num_ent, coll_freq, new_first_did);
 	    tag += make_start_of_chunk(new_is_last_chunk,
 					      new_first_did,
@@ -520,7 +520,7 @@
 
 	    // Now update the last_chunk
 	    cursor->read_tag();
-	    string tag = cursor->current_tag;
+	    std::string tag = cursor->current_tag;
 
 	    const char *tagpos = tag.data();
 	    const char *tagend = tagpos + tag.size();
@@ -558,7 +558,7 @@
 	 *
 	 * The subcases just affect the chunk header.
 	 */
-	string tag;
+	std::string tag;
 
 	/* First write the header, which depends on whether this is the
 	 * first chunk.
@@ -568,7 +568,7 @@
 	     * and we just have to write this one back to disk.
 	     */
 	    LOGLINE(DB, "PostlistChunkWriter::flush(): rewriting the first chunk, which still has items in it");
-	    string key = ChertPostListTable::make_key(tname);
+	    std::string key = ChertPostListTable::make_key(tname);
 	    bool ok = table->get_exact_entry(key, tag);
 	    (void)ok;
 	    Assert(ok);
@@ -612,7 +612,7 @@
 	if (!C_unpack_uint_preserving_sort(&keypos, keyend, &initial_did)) {
 	    report_read_error(keypos);
 	}
-	string new_key;
+	std::string new_key;
 	if (initial_did != first_did) {
 	    /* The fiddlier case:
 	     * Create a new tag with the correct key, and replace
@@ -667,7 +667,7 @@
  *  standard chunk.
  */
 ChertPostList::ChertPostList(intrusive_ptr<const ChertDatabase> this_db_,
-			     const string & term_,
+			     const std::string & term_,
 			     bool keep_reference)
 	: LeafPostList(term_),
 	  this_db(keep_reference ? this_db_ : NULL),
@@ -676,7 +676,7 @@
 	  cursor(this_db_->postlist_table.cursor_get())
 {
     LOGCALL_CTOR(DB, "ChertPostList", this_db_.get() | term_ | keep_reference);
-    string key = ChertPostListTable::make_key(term);
+    std::string key = ChertPostListTable::make_key(term);
     int found = cursor->find_entry(key);
     if (!found) {
 	LOGLINE(DB, "postlist for term not found");
@@ -701,7 +701,7 @@
     read_wdf(&pos, end, &wdf);
     // This works even if there's only one entry (when wdf == collfreq)
     // or when collfreq is 0 (=> wdf is 0 too).
-    wdf_upper_bound = max(collfreq - wdf, wdf);
+    wdf_upper_bound = std::max(collfreq - wdf, wdf);
     LOGLINE(DB, "Initial docid " << did);
 }
 
@@ -988,13 +988,13 @@
 
 // Returns the last did to allow in this chunk.
 Xapian::docid
-ChertPostListTable::get_chunk(const string &tname,
+ChertPostListTable::get_chunk(const std::string &tname,
 	  Xapian::docid did, bool adding,
 	  PostlistChunkReader ** from, PostlistChunkWriter **to)
 {
     LOGCALL(DB, Xapian::docid, "ChertPostListTable::get_chunk", tname | did | adding | from | to);
     // Get chunk containing entry
-    string key = make_key(tname, did);
+    std::string key = make_key(tname, did);
 
     // Find the right chunk
     AutoPtr<ChertCursor> cursor(cursor_get());
@@ -1070,9 +1070,9 @@
 
 void
 ChertPostListTable::merge_changes(
-    const map<string, map<Xapian::docid, pair<char, Xapian::termcount> > > & mod_plists,
-    const map<Xapian::docid, Xapian::termcount> & doclens,
-    const map<string, pair<Xapian::termcount_diff, Xapian::termcount_diff> > & freq_deltas)
+    const std::map<string, std::map<Xapian::docid, std::pair<char, Xapian::termcount> > > & mod_plists,
+    const std::map<Xapian::docid, Xapian::termcount> & doclens,
+    const std::map<string, std::pair<Xapian::termcount_diff, Xapian::termcount_diff> > & freq_deltas)
 {
     LOGCALL_VOID(DB, "ChertPostListTable::merge_changes", mod_plists | doclens | freq_deltas);
 
@@ -1082,15 +1082,15 @@
     LOGVALUE(DB, doclens.size());
     if (!doclens.empty()) {
 	// Ensure there's a first chunk.
-	string current_key = make_key(string());
+	std::string current_key = make_key(string());
 	if (!key_exists(current_key)) {
 	    LOGLINE(DB, "Adding dummy first chunk");
-	    string newtag = make_start_of_first_chunk(0, 0, 0);
+	    std::string newtag = make_start_of_first_chunk(0, 0, 0);
 	    newtag += make_start_of_chunk(true, 0, 0);
 	    add(current_key, newtag);
 	}
 
-	map<Xapian::docid, Xapian::termcount>::const_iterator j;
+	std::map<Xapian::docid, Xapian::termcount>::const_iterator j;
 	j = doclens.begin();
 	Assert(j != doclens.end()); // This case is caught above.
 
@@ -1138,18 +1138,18 @@
 	delete to;
     }
 
-    map<string, map<Xapian::docid, pair<char, Xapian::termcount> > >::const_iterator i;
+    std::map<string, std::map<Xapian::docid, std::pair<char, Xapian::termcount> > >::const_iterator i;
     for (i = mod_plists.begin(); i != mod_plists.end(); ++i) {
 	if (i->second.empty()) continue;
-	string tname = i->first;
+	std::string tname = i->first;
 	{
 	    // Rewrite the first chunk of this posting list with the updated
 	    // termfreq and collfreq.
-	    map<string, pair<Xapian::termcount_diff, Xapian::termcount_diff> >::const_iterator deltas = freq_deltas.find(tname);
+	    std::map<string, std::pair<Xapian::termcount_diff, Xapian::termcount_diff> >::const_iterator deltas = freq_deltas.find(tname);
 	    Assert(deltas != freq_deltas.end());
 
-	    string current_key = make_key(tname);
-	    string tag;
+	    std::string current_key = make_key(tname);
+	    std::string tag;
 	    (void)get_exact_entry(current_key, tag);
 
 	    // Read start of first chunk to get termfreq and collfreq.
@@ -1195,7 +1195,7 @@
 	    collfreq += deltas->second.second;
 
 	    // Rewrite start of first chunk to update termfreq and collfreq.
-	    string newhdr = make_start_of_first_chunk(termfreq, collfreq, firstdid);
+	    std::string newhdr = make_start_of_first_chunk(termfreq, collfreq, firstdid);
 	    newhdr += make_start_of_chunk(islast, firstdid, lastdid);
 	    if (pos == end) {
 		add(current_key, newhdr);
@@ -1205,7 +1205,7 @@
 		add(current_key, tag);
 	    }
 	}
-	map<Xapian::docid, pair<char, Xapian::termcount> >::const_iterator j;
+	std::map<Xapian::docid, std::pair<char, Xapian::termcount> >::const_iterator j;
 	j = i->second.begin();
 	Assert(j != i->second.end()); // This case is caught above.
 
diff -ur xapian-core-1.4.21/backends/chert/chert_postlist.h xapian-core-1.4.21/backends/chert/chert_postlist.h
--- xapian-core-1.4.21/backends/chert/chert_postlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_postlist.h	2022-11-08 16:44:00.960513118 +0100
@@ -36,7 +36,7 @@
 #include <map>
 #include <string>
 
-using namespace std;
+using std::string;
 
 class ChertCursor;
 class ChertDatabase;
@@ -65,7 +65,7 @@
 	 *  @param readonly_      - whether to open the table for read only
 	 *                          access.
 	 */
-	ChertPostListTable(const string & path_, bool readonly_)
+	ChertPostListTable(const std::string & path_, bool readonly_)
 	    : ChertTable("postlist", path_ + "/postlist.", readonly_),
 	      doclen_pl()
 	{ }
@@ -77,26 +77,26 @@
 
 	/// Merge added, removed, and changed entries.
 	void merge_changes(
-	    const map<string, map<Xapian::docid, pair<char, Xapian::termcount> > > & mod_plists,
-	    const map<Xapian::docid, Xapian::termcount> & doclens,
-	    const map<string, pair<Xapian::termcount_diff, Xapian::termcount_diff> > & freq_deltas);
+	    const std::map<string, std::map<Xapian::docid, std::pair<char, Xapian::termcount> > > & mod_plists,
+	    const std::map<Xapian::docid, Xapian::termcount> & doclens,
+	    const std::map<string, std::pair<Xapian::termcount_diff, Xapian::termcount_diff> > & freq_deltas);
 
-	Xapian::docid get_chunk(const string &tname,
+	Xapian::docid get_chunk(const std::string &tname,
 		Xapian::docid did, bool adding,
 		Chert::PostlistChunkReader ** from,
 		Chert::PostlistChunkWriter **to);
 
 	/// Compose a key from a termname and docid.
-	static string make_key(const string & term, Xapian::docid did) {
+	static std::string make_key(const std::string & term, Xapian::docid did) {
 	    return pack_chert_postlist_key(term, did);
 	}
 
 	/// Compose a key from a termname.
-	static string make_key(const string & term) {
+	static std::string make_key(const std::string & term) {
 	    return pack_chert_postlist_key(term);
 	}
 
-	bool term_exists(const string & term) const {
+	bool term_exists(const std::string & term) const {
 	    return key_exists(make_key(term));
 	}
 
@@ -231,7 +231,7 @@
     public:
 	/// Default constructor.
 	ChertPostList(Xapian::Internal::intrusive_ptr<const ChertDatabase> this_db_,
-		      const string & term,
+		      const std::string & term,
 		      bool keep_reference);
 
 	/// Destructor.
diff -ur xapian-core-1.4.21/backends/chert/chert_record.cc xapian-core-1.4.21/backends/chert/chert_record.cc
--- xapian-core-1.4.21/backends/chert/chert_record.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_record.cc	2022-11-08 16:44:15.388461828 +0100
@@ -34,7 +34,7 @@
 inline string
 make_key(Xapian::docid did)
 {
-    string key;
+    std::string key;
     C_pack_uint_preserving_sort(key, did);
     return key;
 }
@@ -43,9 +43,9 @@
 ChertRecordTable::get_record(Xapian::docid did) const
 {
     LOGCALL(DB, string, "ChertRecordTable::get_record", did);
-    string tag;
+    std::string tag;
     // get_document() checks that the docid is valid, unless DOC_ASSUME_VALID
-    // is used in which case returning an empty string here is the most
+    // is used in which case returning an empty std::string here is the most
     // sensible behaviour.
     (void)get_exact_entry(make_key(did), tag);
     RETURN(tag);
@@ -65,7 +65,7 @@
 }
 
 void
-ChertRecordTable::replace_record(const string & data, Xapian::docid did)
+ChertRecordTable::replace_record(const std::string & data, Xapian::docid did)
 {
     LOGCALL_VOID(DB, "ChertRecordTable::replace_record", data | did);
     add(make_key(did), data);
diff -ur xapian-core-1.4.21/backends/chert/chert_record.h xapian-core-1.4.21/backends/chert/chert_record.h
--- xapian-core-1.4.21/backends/chert/chert_record.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_record.h	2022-11-08 16:44:00.944513174 +0100
@@ -30,7 +30,7 @@
 #include "chert_types.h"
 #include "chert_table.h"
 
-using namespace std;
+using std::string;
 
 /** A record in a chert database.
  */
@@ -48,12 +48,12 @@
 	 *  @param readonly_      - whether to open the table for read only
 	 *                          access.
 	 */
-	ChertRecordTable(const string & path_, bool readonly_)
+	ChertRecordTable(const std::string & path_, bool readonly_)
 	    : ChertTable("record", path_ + "/record.", readonly_, Z_DEFAULT_STRATEGY) { }
 
 	/** Retrieve a document from the table.
 	 */
-	string get_record(Xapian::docid did) const;
+	std::string get_record(Xapian::docid did) const;
 
 	/** Get the number of records in the table.
 	 */
@@ -63,7 +63,7 @@
 	 *
 	 * @param did	The document ID to use.
 	 */
-	void replace_record(const string & data, Xapian::docid did);
+	void replace_record(const std::string & data, Xapian::docid did);
 
 	/** Delete a record from the table.
 	 */
diff -ur xapian-core-1.4.21/backends/chert/chert_replicate_internal.h xapian-core-1.4.21/backends/chert/chert_replicate_internal.h
--- xapian-core-1.4.21/backends/chert/chert_replicate_internal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_replicate_internal.h	2022-11-08 16:44:00.948513161 +0100
@@ -22,7 +22,7 @@
 #ifndef XAPIAN_INCLUDED_CHERT_REPLICATE_INTERNAL_H
 #define XAPIAN_INCLUDED_CHERT_REPLICATE_INTERNAL_H
 
-// Magic string used to recognise a changeset file.
+// Magic std::string used to recognise a changeset file.
 #define CHANGES_MAGIC_STRING "ChertChanges"
 
 // The current version of changeset files.
diff -ur xapian-core-1.4.21/backends/chert/chert_spelling.cc xapian-core-1.4.21/backends/chert/chert_spelling.cc
--- xapian-core-1.4.21/backends/chert/chert_spelling.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_spelling.cc	2022-11-08 16:44:15.388461828 +0100
@@ -50,14 +50,14 @@
 	auto d = changes.begin();
 	if (d == changes.end()) continue;
 
-	string updated;
-	string current;
+	std::string updated;
+	std::string current;
 	PrefixCompressedStringWriter out(updated);
 	if (get_exact_entry(key, current)) {
 	    PrefixCompressedStringItor in(current);
 	    updated.reserve(current.size()); // FIXME plus some?
 	    while (!in.at_end() && d != changes.end()) {
-		const string & word = *in;
+		const std::string & word = *in;
 		Assert(d != changes.end());
 		int cmp = word.compare(*d);
 		if (cmp < 0) {
@@ -91,11 +91,11 @@
     }
     termlist_deltas.clear();
 
-    map<string, Xapian::termcount>::const_iterator j;
+    std::map<string, Xapian::termcount>::const_iterator j;
     for (j = wordfreq_changes.begin(); j != wordfreq_changes.end(); ++j) {
-	string key = "W" + j->first;
+	std::string key = "W" + j->first;
 	if (j->second) {
-	    string tag;
+	    std::string tag;
 	    pack_uint_last(tag, j->second);
 	    add(key, tag);
 	} else {
@@ -106,7 +106,7 @@
 }
 
 void
-ChertSpellingTable::toggle_fragment(fragment frag, const string & word)
+ChertSpellingTable::toggle_fragment(fragment frag, const std::string & word)
 {
     auto i = termlist_deltas.find(frag);
     if (i == termlist_deltas.end()) {
@@ -122,11 +122,11 @@
 }
 
 void
-ChertSpellingTable::add_word(const string & word, Xapian::termcount freqinc)
+ChertSpellingTable::add_word(const std::string & word, Xapian::termcount freqinc)
 {
     if (word.size() <= 1) return;
 
-    map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
+    std::map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	// Word "word" already exists and has been modified.
 	if (i->second) {
@@ -137,8 +137,8 @@
 	// we need to execute the code below to re-add trigrams for it.
 	i->second = freqinc;
     } else {
-	string key = "W" + word;
-	string data;
+	std::string key = "W" + word;
+	std::string data;
 	if (get_exact_entry(key, data)) {
 	    // Word "word" already exists, so increment its count.
 	    Xapian::termcount freq;
@@ -157,11 +157,11 @@
 }
 
 void
-ChertSpellingTable::remove_word(const string & word, Xapian::termcount freqdec)
+ChertSpellingTable::remove_word(const std::string & word, Xapian::termcount freqdec)
 {
     if (word.size() <= 1) return;
 
-    map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
+    std::map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	if (i->second == 0) {
 	    // Word has already been deleted.
@@ -176,8 +176,8 @@
 	// Mark word as deleted.
 	i->second = 0;
     } else {
-	string key = "W" + word;
-	string data;
+	std::string key = "W" + word;
+	std::string data;
 	if (!get_exact_entry(key, data)) {
 	    // This word doesn't exist.
 	    return;
@@ -201,7 +201,7 @@
 }
 
 void
-ChertSpellingTable::toggle_word(const string & word)
+ChertSpellingTable::toggle_word(const std::string & word)
 {
     fragment buf;
     // Head:
@@ -251,7 +251,7 @@
 };
 
 TermList *
-ChertSpellingTable::open_termlist(const string & word)
+ChertSpellingTable::open_termlist(const std::string & word)
 {
     // This should have been handled by Database::get_spelling_suggestion().
     AssertRel(word.size(),>,1);
@@ -262,9 +262,9 @@
 
     // Build a priority queue of TermList objects which returns those of
     // greatest approximate size first.
-    priority_queue<TermList*, vector<TermList*>, TermListGreaterApproxSize> pq;
+    priority_queue<TermList*, std::vector<TermList*>, TermListGreaterApproxSize> pq;
     try {
-	string data;
+	std::string data;
 	fragment buf;
 
 	// Head:
@@ -367,17 +367,17 @@
 }
 
 Xapian::doccount
-ChertSpellingTable::get_word_frequency(const string & word) const
+ChertSpellingTable::get_word_frequency(const std::string & word) const
 {
-    map<string, Xapian::termcount>::const_iterator i;
+    std::map<string, Xapian::termcount>::const_iterator i;
     i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	// Modified frequency for word:
 	return i->second;
     }
 
-    string key = "W" + word;
-    string data;
+    std::string key = "W" + word;
+    std::string data;
     if (get_exact_entry(key, data)) {
 	// Word "word" already exists.
 	Xapian::termcount freq;
@@ -442,7 +442,7 @@
 }
 
 TermList *
-ChertSpellingTermList::skip_to(const string & term)
+ChertSpellingTermList::skip_to(const std::string & term)
 {
     while (!data.empty() && current_term < term) {
 	(void)ChertSpellingTermList::next();
diff -ur xapian-core-1.4.21/backends/chert/chert_spellingwordslist.cc xapian-core-1.4.21/backends/chert/chert_spellingwordslist.cc
--- xapian-core-1.4.21/backends/chert/chert_spellingwordslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_spellingwordslist.cc	2022-11-08 16:44:15.388461828 +0100
@@ -82,7 +82,7 @@
 }
 
 TermList *
-ChertSpellingWordsList::skip_to(const string &tname)
+ChertSpellingWordsList::skip_to(const std::string &tname)
 {
     LOGCALL(DB, TermList *, "ChertSpellingWordsList::skip_to", tname);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/chert/chert_synonym.cc xapian-core-1.4.21/backends/chert/chert_synonym.cc
--- xapian-core-1.4.21/backends/chert/chert_synonym.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_synonym.cc	2022-11-08 16:44:15.384461842 +0100
@@ -47,11 +47,11 @@
     if (last_synonyms.empty()) {
 	del(last_term);
     } else {
-	string tag;
+	std::string tag;
 
 	set<string>::const_iterator i;
 	for (i = last_synonyms.begin(); i != last_synonyms.end(); ++i) {
-	    const string & synonym = *i;
+	    const std::string & synonym = *i;
 	    tag += uint8_t(synonym.size() ^ MAGIC_XOR_VALUE);
 	    tag += synonym;
 	}
@@ -63,13 +63,13 @@
 }
 
 void
-ChertSynonymTable::add_synonym(const string & term, const string & synonym)
+ChertSynonymTable::add_synonym(const std::string & term, const std::string & synonym)
 {
     if (last_term != term) {
 	merge_changes();
 	last_term = term;
 
-	string tag;
+	std::string tag;
 	if (get_exact_entry(term, tag)) {
 	    const char * p = tag.data();
 	    const char * end = p + tag.size();
@@ -89,13 +89,13 @@
 }
 
 void
-ChertSynonymTable::remove_synonym(const string & term, const string & synonym)
+ChertSynonymTable::remove_synonym(const std::string & term, const std::string & synonym)
 {
     if (last_term != term) {
 	merge_changes();
 	last_term = term;
 
-	string tag;
+	std::string tag;
 	if (get_exact_entry(term, tag)) {
 	    const char * p = tag.data();
 	    const char * end = p + tag.size();
@@ -115,7 +115,7 @@
 }
 
 void
-ChertSynonymTable::clear_synonyms(const string & term)
+ChertSynonymTable::clear_synonyms(const std::string & term)
 {
     // We don't actually ever need to merge_changes() here, but it's quite
     // likely that someone might clear_synonyms() and then add_synonym() for
@@ -131,9 +131,9 @@
 }
 
 TermList *
-ChertSynonymTable::open_termlist(const string & term)
+ChertSynonymTable::open_termlist(const std::string & term)
 {
-    vector<string> synonyms;
+    std::vector<string> synonyms;
 
     if (last_term == term) {
 	if (last_synonyms.empty()) return NULL;
@@ -144,7 +144,7 @@
 	    synonyms.push_back(*i);
 	}
     } else {
-	string tag;
+	std::string tag;
 	if (!get_exact_entry(term, tag)) return NULL;
 
 	const char * p = tag.data();
@@ -203,7 +203,7 @@
 }
 
 TermList *
-ChertSynonymTermList::skip_to(const string &tname)
+ChertSynonymTermList::skip_to(const std::string &tname)
 {
     LOGCALL(DB, TermList *, "ChertSynonymTermList::skip_to", tname);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/chert/chert_synonym.h xapian-core-1.4.21/backends/chert/chert_synonym.h
--- xapian-core-1.4.21/backends/chert/chert_synonym.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_synonym.h	2022-11-08 16:44:00.956513132 +0100
@@ -126,12 +126,12 @@
     ChertCursor * cursor;
 
     /// The prefix to restrict the terms to.
-    string prefix;
+    std::string prefix;
 
   public:
     ChertSynonymTermList(Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> database_,
 		      ChertCursor * cursor_,
-		      const string & prefix_)
+		      const std::string & prefix_)
 	    : database(database_), cursor(cursor_), prefix(prefix_)
     {
 	// Position the cursor on the highest key before the first key we want,
@@ -153,7 +153,7 @@
      *  Either next() or skip_to() must have been called before this
      *  method can be called.
      */
-    string get_termname() const;
+    std::string get_termname() const;
 
     /// Return the term frequency for the term at the current position.
     Xapian::doccount get_termfreq() const;
@@ -162,7 +162,7 @@
     TermList * next();
 
     /// Advance to the first term which is >= tname.
-    TermList * skip_to(const string &tname);
+    TermList * skip_to(const std::string &tname);
 
     /// True if we're off the end of the list
     bool at_end() const;
diff -ur xapian-core-1.4.21/backends/chert/chert_table.cc xapian-core-1.4.21/backends/chert/chert_table.cc
--- xapian-core-1.4.21/backends/chert/chert_table.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_table.cc	2022-11-08 16:44:15.408461757 +0100
@@ -183,7 +183,7 @@
 
     int dir_end = DIR_END(p);
     if (rare(dir_end < DIR_START || unsigned(dir_end) > block_size)) {
-	string msg("dir_end invalid in block ");
+	std::string msg("dir_end invalid in block ");
 	msg += str(n);
 	throw Xapian::DatabaseCorruptError(msg);
     }
@@ -303,7 +303,7 @@
     }
 
     if (rare(j != GET_LEVEL(p))) {
-	string msg = "Expected block ";
+	std::string msg = "Expected block ";
 	msg += str(n);
 	msg += " to be level ";
 	msg += str(j);
@@ -945,7 +945,7 @@
 K set accordingly. c is set to 1.
 */
 
-void ChertTable::form_key(const string & key) const
+void ChertTable::form_key(const std::string & key) const
 {
     LOGCALL_VOID(DB, "ChertTable::form_key", key);
     kt.form_key(key);
@@ -975,7 +975,7 @@
 */
 
 void
-ChertTable::add(const string &key, string tag, bool already_compressed)
+ChertTable::add(const std::string &key, std::string tag, bool already_compressed)
 {
     LOGCALL_VOID(DB, "ChertTable::add", key | tag | already_compressed);
     Assert(writable);
@@ -1102,7 +1102,7 @@
 */
 
 bool
-ChertTable::del(const string &key)
+ChertTable::del(const std::string &key)
 {
     LOGCALL(DB, bool, "ChertTable::del", key);
     Assert(writable);
@@ -1138,7 +1138,7 @@
 }
 
 bool
-ChertTable::readahead_key(const string &key) const
+ChertTable::readahead_key(const std::string &key) const
 {
     LOGCALL(DB, bool, "ChertTable::readahead_key", key);
     Assert(!key.empty());
@@ -1184,7 +1184,7 @@
 }
 
 bool
-ChertTable::get_exact_entry(const string &key, string & tag) const
+ChertTable::get_exact_entry(const std::string &key, std::string & tag) const
 {
     LOGCALL(DB, bool, "ChertTable::get_exact_entry", key | tag);
     Assert(!key.empty());
@@ -1207,7 +1207,7 @@
 }
 
 bool
-ChertTable::key_exists(const string &key) const
+ChertTable::key_exists(const std::string &key) const
 {
     LOGCALL(DB, bool, "ChertTable::key_exists", key);
     Assert(!key.empty());
@@ -1220,7 +1220,7 @@
 }
 
 bool
-ChertTable::read_tag(Cursor * C_, string *tag, bool keep_compressed) const
+ChertTable::read_tag(Cursor * C_, std::string *tag, bool keep_compressed) const
 {
     LOGCALL(DB, bool, "ChertTable::read_tag", Literal("C_") | tag | keep_compressed);
     Item item(C_[0].p, C_[0].c);
@@ -1250,7 +1250,7 @@
     // don't need both the full compressed and uncompressed tags in memory
     // at once.
 
-    string utag;
+    std::string utag;
     // May not be enough for a compressed tag, but it's a reasonable guess.
     utag.reserve(tag->size() + tag->size() / 2);
 
@@ -1279,7 +1279,7 @@
 
 	if (err != Z_OK && err != Z_STREAM_END) {
 	    if (err == Z_MEM_ERROR) throw std::bad_alloc();
-	    string msg = "inflate failed";
+	    std::string msg = "inflate failed";
 	    if (inflate_zstream->msg) {
 		msg += " (";
 		msg += inflate_zstream->msg;
@@ -1292,7 +1292,7 @@
 		    inflate_zstream->next_out - buf);
     }
     if (utag.size() != inflate_zstream->total_out) {
-	string msg = "compressed tag didn't expand to the expected size: ";
+	std::string msg = "compressed tag didn't expand to the expected size: ";
 	msg += str(utag.size());
 	msg += " != ";
 	// OpenBSD's zlib.h uses off_t instead of uLong for total_out.
@@ -1337,7 +1337,7 @@
 
     {
 	const size_t BTREE_BASES = 2;
-	string err_msg;
+	std::string err_msg;
 	static const char basenames[BTREE_BASES] = { 'A', 'B' };
 
 	ChertTable_base bases[BTREE_BASES];
@@ -1362,7 +1362,7 @@
 		::close(handle);
 		handle = -1;
 	    }
-	    string message = "Error opening table '";
+	    std::string message = "Error opening table '";
 	    message += name;
 	    message += "':\n";
 	    message += err_msg;
@@ -1520,7 +1520,7 @@
 	    revision_number = revision_;
 	    RETURN(true);
 	}
-	string message(create_db ? "Couldn't create " : "Couldn't open ");
+	std::string message(create_db ? "Couldn't create " : "Couldn't open ");
 	message += name;
 	message += "DB read/write: ";
 	errno_to_string(errno, message);
@@ -1557,7 +1557,7 @@
     RETURN(true);
 }
 
-ChertTable::ChertTable(const char * tablename_, const string & path_,
+ChertTable::ChertTable(const char * tablename_, const std::string & path_,
 		       bool readonly_, int compress_strategy_, bool lazy_)
 	: tablename(tablename_),
 	  revision_number(0),
@@ -1633,7 +1633,7 @@
 	    deflate_zstream = 0;
 	    throw std::bad_alloc();
 	}
-	string msg = "deflateInit2 failed (";
+	std::string msg = "deflateInit2 failed (";
 	if (deflate_zstream->msg) {
 	    msg += deflate_zstream->msg;
 	} else {
@@ -1670,7 +1670,7 @@
 	    inflate_zstream = 0;
 	    throw std::bad_alloc();
 	}
-	string msg = "inflateInit2 failed (";
+	std::string msg = "inflateInit2 failed (";
 	if (inflate_zstream->msg) {
 	    msg += inflate_zstream->msg;
 	} else {
@@ -1822,7 +1822,7 @@
 
 void
 ChertTable::commit(chert_revision_number_t revision, int changes_fd,
-		   const string * changes_tail)
+		   const std::string * changes_tail)
 {
     LOGCALL_VOID(DB, "ChertTable::commit", revision | changes_fd | changes_tail);
     Assert(writable);
@@ -1868,9 +1868,9 @@
 
 	// Save to "<table>.tmp" and then rename to "<table>.base<letter>" so
 	// that a reader can't try to read a partially written base file.
-	string tmp = name;
+	std::string tmp = name;
 	tmp += "tmp";
-	string basefile = name;
+	std::string basefile = name;
 	basefile += "base";
 	basefile += char(base_letter);
 	base.write_to_file(tmp, base_letter, tablename, changes_fd, changes_tail);
@@ -1886,7 +1886,7 @@
 	}
 
 	if (!io_tmp_rename(tmp, basefile)) {
-	    string msg("Couldn't update base file ");
+	    std::string msg("Couldn't update base file ");
 	    msg += basefile;
 	    throw Xapian::DatabaseError(msg, errno);
 	}
@@ -1911,7 +1911,7 @@
     if (handle < 0) return;
     if (faked_root_block) return;
 
-    string buf;
+    std::string buf;
     pack_uint(buf, 2u); // Indicate the item is a list of blocks
     pack_string(buf, tablename);
     pack_uint(buf, block_size);
@@ -1963,7 +1963,7 @@
 
     // This causes problems: if (!Btree_modified) return;
 
-    string err_msg;
+    std::string err_msg;
     if (!base.read(name, base_letter, writable, err_msg)) {
 	throw Xapian::DatabaseCorruptError(string("Couldn't reread base ") + base_letter);
     }
@@ -2013,7 +2013,7 @@
 	    revision_number = revision_;
 	    RETURN(true);
 	}
-	string message("Couldn't open ");
+	std::string message("Couldn't open ");
 	message += name;
 	message += "DB to read: ";
 	errno_to_string(errno, message);
diff -ur xapian-core-1.4.21/backends/chert/chert_table.h xapian-core-1.4.21/backends/chert/chert_table.h
--- xapian-core-1.4.21/backends/chert/chert_table.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_table.h	2022-11-08 16:44:00.960513118 +0100
@@ -391,7 +391,7 @@
 	 */
 	void close(bool permanent = false);
 
-	bool readahead_key(const string &key) const;
+	bool readahead_key(const std::string &key) const;
 
 	/** Determine whether the btree exists on disk.
 	 */
@@ -669,7 +669,7 @@
 	/// Throw an exception indicating that the database is closed.
 	XAPIAN_NORETURN(static void throw_database_closed());
 
-	string get_path() const {
+	std::string get_path() const {
 	    return name;
 	}
 
diff -ur xapian-core-1.4.21/backends/chert/chert_termlist.cc xapian-core-1.4.21/backends/chert/chert_termlist.cc
--- xapian-core-1.4.21/backends/chert/chert_termlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_termlist.cc	2022-11-08 16:44:15.392461814 +0100
@@ -170,7 +170,7 @@
 }
 
 TermList *
-ChertTermList::skip_to(const string & term)
+ChertTermList::skip_to(const std::string & term)
 {
     LOGCALL(API, TermList *, "ChertTermList::skip_to", term);
     while (pos != NULL && current_term < term) {
diff -ur xapian-core-1.4.21/backends/chert/chert_termlisttable.cc xapian-core-1.4.21/backends/chert/chert_termlisttable.cc
--- xapian-core-1.4.21/backends/chert/chert_termlisttable.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_termlisttable.cc	2022-11-08 16:44:15.392461814 +0100
@@ -42,7 +42,7 @@
 {
     LOGCALL_VOID(DB, "ChertTermListTable::set_termlist", did | doc | doclen);
 
-    string tag;
+    std::string tag;
     pack_uint(tag, doclen);
 
     Xapian::doccount termlist_size = doc.termlist_count();
@@ -57,7 +57,7 @@
     Xapian::TermIterator t = doc.termlist_begin();
     if (t != doc.termlist_end()) {
 	pack_uint(tag, termlist_size);
-	string prev_term = *t;
+	std::string prev_term = *t;
 
 	tag += prev_term.size();
 	tag += prev_term;
@@ -65,7 +65,7 @@
 	--termlist_size;
 
 	while (++t != doc.termlist_end()) {
-	    const string & term = *t;
+	    const std::string & term = *t;
 	    // If there's a shared prefix with the previous term, we don't
 	    // store it explicitly, but just store the length of the shared
 	    // prefix.  In general, this is a big win.
diff -ur xapian-core-1.4.21/backends/chert/chert_valuelist.cc xapian-core-1.4.21/backends/chert/chert_valuelist.cc
--- xapian-core-1.4.21/backends/chert/chert_valuelist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_valuelist.cc	2022-11-08 16:44:15.384461842 +0100
@@ -36,7 +36,7 @@
     if (!first_did) return false;
 
     cursor->read_tag();
-    const string & tag = cursor->current_tag;
+    const std::string & tag = cursor->current_tag;
     reader.assign(tag.data(), tag.size(), first_did);
     return true;
 }
@@ -164,7 +164,7 @@
 string
 ChertValueList::get_description() const
 {
-    string desc("ChertValueList(slot=");
+    std::string desc("ChertValueList(slot=");
     desc += str(slot);
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/backends/chert/chert_values.cc xapian-core-1.4.21/backends/chert/chert_values.cc
--- xapian-core-1.4.21/backends/chert/chert_values.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_values.cc	2022-11-08 16:44:15.412461742 +0100
@@ -51,7 +51,7 @@
     // Add an extra character so that it can't clash with a termlist entry key
     // and will sort just after the corresponding termlist entry key.
     // FIXME: should we store this in the *same entry* as the list of terms?
-    string key;
+    std::string key;
     C_pack_uint_preserving_sort(key, did);
     key += '\0';
     RETURN(key);
@@ -62,7 +62,7 @@
 make_valuestats_key(Xapian::valueno slot)
 {
     LOGCALL_STATIC(DB, string, "make_valuestats_key", slot);
-    string key("\0\xd0", 2);
+    std::string key("\0\xd0", 2);
     pack_uint_last(key, slot);
     RETURN(key);
 }
@@ -130,12 +130,12 @@
 
 void
 ChertValueManager::add_value(Xapian::docid did, Xapian::valueno slot,
-			     const string & val)
+			     const std::string & val)
 {
-    map<Xapian::valueno, map<Xapian::docid, string> >::iterator i;
+    std::map<Xapian::valueno, std::map<Xapian::docid, string> >::iterator i;
     i = changes.find(slot);
     if (i == changes.end()) {
-	i = changes.insert(make_pair(slot, map<Xapian::docid, string>())).first;
+	i = changes.insert(make_pair(slot, std::map<Xapian::docid, string>())).first;
     }
     i->second[did] = val;
 }
@@ -143,10 +143,10 @@
 void
 ChertValueManager::remove_value(Xapian::docid did, Xapian::valueno slot)
 {
-    map<Xapian::valueno, map<Xapian::docid, string> >::iterator i;
+    std::map<Xapian::valueno, std::map<Xapian::docid, string> >::iterator i;
     i = changes.find(slot);
     if (i == changes.end()) {
-	i = changes.insert(make_pair(slot, map<Xapian::docid, string>())).first;
+	i = changes.insert(make_pair(slot, std::map<Xapian::docid, string>())).first;
     }
     i->second[did] = string();
 }
@@ -154,7 +154,7 @@
 Xapian::docid
 ChertValueManager::get_chunk_containing_did(Xapian::valueno slot,
 					    Xapian::docid did,
-					    string &chunk) const
+					    std::string &chunk) const
 {
     LOGCALL(DB, Xapian::docid, "ChertValueManager::get_chunk_containing_did", slot | did | chunk);
     if (!cursor.get())
@@ -197,11 +197,11 @@
 
     Xapian::valueno slot;
 
-    string ctag;
+    std::string ctag;
 
     ValueChunkReader reader;
 
-    string tag;
+    std::string tag;
 
     Xapian::docid prev_did;
 
@@ -211,7 +211,7 @@
 
     Xapian::docid last_allowed_did;
 
-    void append_to_stream(Xapian::docid did, const string & value) {
+    void append_to_stream(Xapian::docid did, const std::string & value) {
 	Assert(did);
 	if (tag.empty()) {
 	    new_first_did = did;
@@ -249,13 +249,13 @@
 	write_tag();
     }
 
-    void update(Xapian::docid did, const string & value) {
+    void update(Xapian::docid did, const std::string & value) {
 	if (last_allowed_did && did > last_allowed_did) {
 	    // The next change needs to go in a later existing chunk than the
 	    // one we're currently updating, so we copy over the rest of the
 	    // entries from the current chunk, write out the updated chunk and
 	    // drop through to the case below will read in that later chunk.
-	    // FIXME: use some string splicing magic instead of this loop.
+	    // FIXME: use some std::string splicing magic instead of this loop.
 	    while (!reader.at_end()) {
 		// last_allowed_did should be an upper bound for this chunk.
 		AssertRel(reader.get_docid(),<=,last_allowed_did);
@@ -294,7 +294,7 @@
 		reader.assign(ctag.data(), ctag.size(), first_did);
 	    }
 	    if (cursor->next()) {
-		const string & key = cursor->current_key;
+		const std::string & key = cursor->current_key;
 		Xapian::docid next_first_did = docid_from_key(slot, key);
 		if (next_first_did) last_allowed_did = next_first_did - 1;
 		Assert(last_allowed_did);
@@ -321,10 +321,10 @@
 ChertValueManager::merge_changes()
 {
     if (termlist_table->is_open()) {
-	map<Xapian::docid, string>::const_iterator i;
+	std::map<Xapian::docid, string>::const_iterator i;
 	for (i = slots.begin(); i != slots.end(); ++i) {
-	    const string & enc = i->second;
-	    string key = make_slot_key(i->first);
+	    const std::string & enc = i->second;
+	    std::string key = make_slot_key(i->first);
 	    if (!enc.empty()) {
 		termlist_table->add(key, i->second);
 	    } else {
@@ -335,12 +335,12 @@
     }
 
     {
-	map<Xapian::valueno, map<Xapian::docid, string> >::const_iterator i;
+	std::map<Xapian::valueno, std::map<Xapian::docid, string> >::const_iterator i;
 	for (i = changes.begin(); i != changes.end(); ++i) {
 	    Xapian::valueno slot = i->first;
 	    ValueUpdater updater(postlist_table, slot);
-	    const map<Xapian::docid, string> & slot_changes = i->second;
-	    map<Xapian::docid, string>::const_iterator j;
+	    const std::map<Xapian::docid, string> & slot_changes = i->second;
+	    std::map<Xapian::docid, string>::const_iterator j;
 	    for (j = slot_changes.begin(); j != slot_changes.end(); ++j) {
 		updater.update(j->first, j->second);
 	    }
@@ -351,16 +351,16 @@
 
 void
 ChertValueManager::add_document(Xapian::docid did, const Xapian::Document &doc,
-				map<Xapian::valueno, ValueStats> & value_stats)
+				std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     // FIXME: Use BitWriter and interpolative coding?  Or is it not worthwhile
     // for this?
-    string slots_used;
+    std::string slots_used;
     Xapian::valueno prev_slot = static_cast<Xapian::valueno>(-1);
     Xapian::ValueIterator it = doc.values_begin();
     while (it != doc.values_end()) {
 	Xapian::valueno slot = it.get_valueno();
-	string value = *it;
+	std::string value = *it;
 	Assert(!value.empty());
 
 	// Update the statistics.
@@ -403,11 +403,11 @@
 
 void
 ChertValueManager::delete_document(Xapian::docid did,
-				   map<Xapian::valueno, ValueStats> & value_stats)
+				   std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     Assert(termlist_table->is_open());
-    map<Xapian::docid, string>::iterator it = slots.find(did);
-    string s;
+    std::map<Xapian::docid, string>::iterator it = slots.find(did);
+    std::string s;
     if (it != slots.end()) {
 	swap(s, it->second);
     } else {
@@ -448,7 +448,7 @@
 void
 ChertValueManager::replace_document(Xapian::docid did,
 				    const Xapian::Document &doc,
-				    map<Xapian::valueno, ValueStats> & value_stats)
+				    std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     // Load the values into the document from the database, if they haven't
     // been already.  (If we don't do this before deleting the old values,
@@ -461,16 +461,16 @@
 string
 ChertValueManager::get_value(Xapian::docid did, Xapian::valueno slot) const
 {
-    map<Xapian::valueno, map<Xapian::docid, string> >::const_iterator i;
+    std::map<Xapian::valueno, std::map<Xapian::docid, string> >::const_iterator i;
     i = changes.find(slot);
     if (i != changes.end()) {
-	map<Xapian::docid, string>::const_iterator j;
+	std::map<Xapian::docid, string>::const_iterator j;
 	j = i->second.find(did);
 	if (j != i->second.end()) return j->second;
     }
 
     // Read it from the table.
-    string chunk;
+    std::string chunk;
     Xapian::docid first_did;
     first_did = get_chunk_containing_did(slot, did, chunk);
     if (first_did == 0) return string();
@@ -482,7 +482,7 @@
 }
 
 void
-ChertValueManager::get_all_values(map<Xapian::valueno, string> & values,
+ChertValueManager::get_all_values(std::map<Xapian::valueno, string> & values,
 				  Xapian::docid did) const
 {
     Assert(values.empty());
@@ -493,8 +493,8 @@
 	    ChertTable::throw_database_closed();
 	throw Xapian::FeatureUnavailableError("Database has no termlist");
     }
-    map<Xapian::docid, string>::const_iterator i = slots.find(did);
-    string s;
+    std::map<Xapian::docid, string>::const_iterator i = slots.find(did);
+    std::string s;
     if (i != slots.end()) {
 	s = i->second;
     } else {
@@ -532,7 +532,7 @@
     // Invalidate the cache first in case an exception is thrown.
     mru_slot = Xapian::BAD_VALUENO;
 
-    string tag;
+    std::string tag;
     if (postlist_table->get_exact_entry(make_valuestats_key(slot), tag)) {
 	const char * pos = tag.data();
 	const char * end = pos + tag.size();
@@ -567,15 +567,15 @@
 }
 
 void
-ChertValueManager::set_value_stats(map<Xapian::valueno, ValueStats> & value_stats)
+ChertValueManager::set_value_stats(std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     LOGCALL_VOID(DB, "ChertValueManager::set_value_stats", value_stats);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     for (i = value_stats.begin(); i != value_stats.end(); ++i) {
-	string key = make_valuestats_key(i->first);
+	std::string key = make_valuestats_key(i->first);
 	const ValueStats & stats = i->second;
 	if (stats.freq != 0) {
-	    string new_value;
+	    std::string new_value;
 	    pack_uint(new_value, stats.freq);
 	    pack_string(new_value, stats.lower_bound);
 	    // We don't store or count empty values, so neither of the bounds
diff -ur xapian-core-1.4.21/backends/chert/chert_version.cc xapian-core-1.4.21/backends/chert/chert_version.cc
--- xapian-core-1.4.21/backends/chert/chert_version.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_version.cc	2022-11-08 16:44:15.404461770 +0100
@@ -69,7 +69,7 @@
     int fd = ::open(filename.c_str(), O_WRONLY|O_CREAT|O_TRUNC|O_BINARY|O_CLOEXEC, 0666);
 
     if (fd < 0) {
-	string msg("Failed to create chert version file: ");
+	std::string msg("Failed to create chert version file: ");
 	msg += filename;
 	throw Xapian::DatabaseOpeningError(msg, errno);
     }
@@ -83,7 +83,7 @@
 
     io_sync(fd);
     if (close(fd) != 0) {
-	string msg("Failed to create chert version file: ");
+	std::string msg("Failed to create chert version file: ");
 	msg += filename;
 	throw Xapian::DatabaseOpeningError(msg, errno);
     }
@@ -95,7 +95,7 @@
     int fd = ::open(filename.c_str(), O_RDONLY|O_BINARY|O_CLOEXEC);
 
     if (fd < 0) {
-	string msg = filename;
+	std::string msg = filename;
 	msg += ": Failed to open chert version file for reading";
 	if (errno == ENOENT || errno == ENOTDIR) {
 	    throw Xapian::DatabaseNotFoundError(msg, errno);
@@ -117,7 +117,7 @@
     if (size != VERSIONFILE_SIZE) {
 	static_assert(VERSIONFILE_SIZE == VERSIONFILE_SIZE_LITERAL,
 		      "VERSIONFILE_SIZE_LITERAL needs updating");
-	string msg = filename;
+	std::string msg = filename;
 	msg += ": Chert version file should be "
 	       STRINGIZE(VERSIONFILE_SIZE_LITERAL)" bytes, actually ";
 	msg += str(size);
@@ -125,7 +125,7 @@
     }
 
     if (memcmp(buf, MAGIC_STRING, MAGIC_LEN) != 0) {
-	string msg = filename;
+	std::string msg = filename;
 	msg += ": Chert version file doesn't contain the right magic string";
 	throw Xapian::DatabaseCorruptError(msg);
     }
@@ -134,7 +134,7 @@
     v = reinterpret_cast<const unsigned char *>(buf) + MAGIC_LEN;
     unsigned int version = v[0] | (v[1] << 8) | (v[2] << 16) | (v[3] << 24);
     if (version != CHERT_VERSION) {
-	string msg = filename;
+	std::string msg = filename;
 	msg += ": Chert version file is version ";
 	msg += str(version);
 	msg += " but I only understand " STRINGIZE(CHERT_VERSION);
diff -ur xapian-core-1.4.21/backends/chert/chert_version.h xapian-core-1.4.21/backends/chert/chert_version.h
--- xapian-core-1.4.21/backends/chert/chert_version.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/chert/chert_version.h	2022-11-08 16:44:00.960513118 +0100
@@ -28,7 +28,7 @@
 
 /** The ChertVersion class manages the "iamchert" file.
  *
- *  The "iamchert" file (currently) contains a "magic" string identifying
+ *  The "iamchert" file (currently) contains a "magic" std::string identifying
  *  that this is a chert database and a database format version number.
  */
 class ChertVersion {
@@ -57,7 +57,7 @@
 	return uuid.data();
     }
 
-    /// Return UUID in the standard 36 character string format.
+    /// Return UUID in the standard 36 character std::string format.
     std::string get_uuid_string() const {
 	return uuid.to_string();
     }
diff -ur xapian-core-1.4.21/backends/contiguousalldocspostlist.cc xapian-core-1.4.21/backends/contiguousalldocspostlist.cc
--- xapian-core-1.4.21/backends/contiguousalldocspostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/contiguousalldocspostlist.cc	2022-11-08 16:44:15.328462041 +0100
@@ -123,7 +123,7 @@
 string
 ContiguousAllDocsPostList::get_description() const
 {
-    string msg("ContiguousAllDocsPostList(1..");
+    std::string msg("ContiguousAllDocsPostList(1..");
     msg += str(doccount);
     msg += ')';
     return msg;
diff -ur xapian-core-1.4.21/backends/contiguousalldocspostlist.h xapian-core-1.4.21/backends/contiguousalldocspostlist.h
--- xapian-core-1.4.21/backends/contiguousalldocspostlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/contiguousalldocspostlist.h	2022-11-08 16:44:00.904513317 +0100
@@ -88,7 +88,7 @@
     /// Always return 1 (wdf isn't totally meaningful for us).
     Xapian::termcount get_wdf_upper_bound() const;
 
-    /// Return a string description of this object.
+    /// Return a std::string description of this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/backends/database.cc xapian-core-1.4.21/backends/database.cc
--- xapian-core-1.4.21/backends/database.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/database.cc	2022-11-08 16:44:15.380461857 +0100
@@ -72,7 +72,7 @@
 }
 
 Xapian::termcount
-Database::Internal::get_wdf_upper_bound(const string & term) const
+Database::Internal::get_wdf_upper_bound(const std::string & term) const
 {
     // Not a very tight bound in general, but this is only a fall-back for
     // backends which don't store these stats.
@@ -173,7 +173,7 @@
 }
 
 void
-Database::Internal::delete_document(const string & unique_term)
+Database::Internal::delete_document(const std::string & unique_term)
 {
     // Default implementation - overridden for remote databases
     intrusive_ptr<LeafPostList> pl(open_post_list(unique_term));
@@ -190,7 +190,7 @@
 }
 
 Xapian::docid
-Database::Internal::replace_document(const string & unique_term,
+Database::Internal::replace_document(const std::string & unique_term,
 				     const Xapian::Document & document)
 {
     // Default implementation - overridden for remote databases
@@ -214,7 +214,7 @@
 }
 
 TermList *
-Database::Internal::open_spelling_termlist(const string &) const
+Database::Internal::open_spelling_termlist(const std::string &) const
 {
     // Only implemented for some database backends - others will just not
     // suggest spelling corrections (or not contribute to them in a multiple
@@ -232,7 +232,7 @@
 }
 
 Xapian::doccount
-Database::Internal::get_spelling_frequency(const string &) const
+Database::Internal::get_spelling_frequency(const std::string &) const
 {
     // Only implemented for some database backends - others will just not
     // suggest spelling corrections (or not contribute to them in a multiple
@@ -241,19 +241,19 @@
 }
 
 void
-Database::Internal::add_spelling(const string &, Xapian::termcount) const
+Database::Internal::add_spelling(const std::string &, Xapian::termcount) const
 {
     throw Xapian::UnimplementedError("This backend doesn't implement spelling correction");
 }
 
 void
-Database::Internal::remove_spelling(const string &, Xapian::termcount) const
+Database::Internal::remove_spelling(const std::string &, Xapian::termcount) const
 {
     throw Xapian::UnimplementedError("This backend doesn't implement spelling correction");
 }
 
 TermList *
-Database::Internal::open_synonym_termlist(const string &) const
+Database::Internal::open_synonym_termlist(const std::string &) const
 {
     // Only implemented for some database backends - others will just not
     // expand synonyms (or not contribute to them in a multiple database
@@ -262,7 +262,7 @@
 }
 
 TermList *
-Database::Internal::open_synonym_keylist(const string &) const
+Database::Internal::open_synonym_keylist(const std::string &) const
 {
     // Only implemented for some database backends - others will just not
     // expand synonyms (or not contribute to them in a multiple database
@@ -271,31 +271,31 @@
 }
 
 void
-Database::Internal::add_synonym(const string &, const string &) const
+Database::Internal::add_synonym(const std::string &, const std::string &) const
 {
     throw Xapian::UnimplementedError("This backend doesn't implement synonyms");
 }
 
 void
-Database::Internal::remove_synonym(const string &, const string &) const
+Database::Internal::remove_synonym(const std::string &, const std::string &) const
 {
     throw Xapian::UnimplementedError("This backend doesn't implement synonyms");
 }
 
 void
-Database::Internal::clear_synonyms(const string &) const
+Database::Internal::clear_synonyms(const std::string &) const
 {
     throw Xapian::UnimplementedError("This backend doesn't implement synonyms");
 }
 
 string
-Database::Internal::get_metadata(const string &) const
+Database::Internal::get_metadata(const std::string &) const
 {
     return string();
 }
 
 TermList *
-Database::Internal::open_metadata_keylist(const string &) const
+Database::Internal::open_metadata_keylist(const std::string &) const
 {
     // Only implemented for some database backends - others will simply report
     // there being no metadata keys.
@@ -303,7 +303,7 @@
 }
 
 void
-Database::Internal::set_metadata(const string &, const string &)
+Database::Internal::set_metadata(const std::string &, const std::string &)
 {
     throw Xapian::UnimplementedError("This backend doesn't implement metadata");
 }
@@ -332,7 +332,7 @@
 }
 
 void
-Database::Internal::write_changesets_to_fd(int, const string &, bool, ReplicationInfo *)
+Database::Internal::write_changesets_to_fd(int, const std::string &, bool, ReplicationInfo *)
 {
     throw Xapian::UnimplementedError("This backend doesn't provide changesets");
 }
diff -ur xapian-core-1.4.21/backends/database.h xapian-core-1.4.21/backends/database.h
--- xapian-core-1.4.21/backends/database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/database.h	2022-11-08 16:44:00.908513303 +0100
@@ -37,7 +37,7 @@
 #include <xapian/termiterator.h>
 #include <xapian/valueiterator.h>
 
-using namespace std;
+using std::string;
 
 class LeafPostList;
 class RemoteDatabase;
@@ -150,7 +150,7 @@
 	 *  @param collfreq_ptr	Point to return number of occurrences of @a
 	 *			term in the database (or NULL not to return)
 	 */
-	virtual void get_freqs(const string & term,
+	virtual void get_freqs(const std::string & term,
 			       Xapian::doccount * termfreq_ptr,
 			       Xapian::termcount * collfreq_ptr) const = 0;
 
@@ -197,7 +197,7 @@
 	 *
 	 *  @param tname  The term whose presence is being checked.
 	 */
-	virtual bool term_exists(const string & tname) const = 0;
+	virtual bool term_exists(const std::string & tname) const = 0;
 
 	/** Check whether this database contains any positional information.
 	 */
@@ -221,7 +221,7 @@
 	 *		  This object must be deleted by the caller after
 	 *                use.
 	 */
-	virtual LeafPostList * open_post_list(const string & tname) const = 0;
+	virtual LeafPostList * open_post_list(const std::string & tname) const = 0;
 
 	/** Open a value stream.
 	 *
@@ -255,7 +255,7 @@
 	 *                This object must be deleted by the caller after
 	 *                use.
 	 */
-	virtual TermList * open_allterms(const string & prefix) const = 0;
+	virtual TermList * open_allterms(const std::string & prefix) const = 0;
 
 	/** Open a position list for the given term in the given document.
 	 *
@@ -269,7 +269,7 @@
 	 *                use.
 	 */
 	virtual PositionList * open_position_list(Xapian::docid did,
-					const string & tname) const = 0;
+					const std::string & tname) const = 0;
 
 	/** Open a document.
 	 *
@@ -295,7 +295,7 @@
 	 *
 	 *  If there are no trigrams, returns NULL.
 	 */
-	virtual TermList * open_spelling_termlist(const string & word) const;
+	virtual TermList * open_spelling_termlist(const std::string & word) const;
 
 	/** Return a termlist which returns the words which are spelling
 	 *  correction targets.
@@ -305,7 +305,7 @@
 	virtual TermList * open_spelling_wordlist() const;
 
 	/** Return the number of times @a word was added as a spelling. */
-	virtual Xapian::doccount get_spelling_frequency(const string & word) const;
+	virtual Xapian::doccount get_spelling_frequency(const std::string & word) const;
 
 	/** Add a word to the spelling dictionary.
 	 *
@@ -314,7 +314,7 @@
 	 *  @param word	    The word to add.
 	 *  @param freqinc  How much to increase its frequency by.
 	 */
-	virtual void add_spelling(const string & word,
+	virtual void add_spelling(const std::string & word,
 				  Xapian::termcount freqinc) const;
 
 	/** Remove a word from the spelling dictionary.
@@ -325,46 +325,46 @@
 	 *  @param word	    The word to remove.
 	 *  @param freqdec  How much to decrease its frequency by.
 	 */
-	virtual void remove_spelling(const string & word,
+	virtual void remove_spelling(const std::string & word,
 				     Xapian::termcount freqdec) const;
 
 	/** Open a termlist returning synonyms for a term.
 	 *
 	 *  If @a term has no synonyms, returns NULL.
 	 */
-	virtual TermList * open_synonym_termlist(const string & term) const;
+	virtual TermList * open_synonym_termlist(const std::string & term) const;
 
 	/** Open a termlist returning each term which has synonyms.
 	 *
 	 *  @param prefix   If non-empty, only terms with this prefix are
 	 *		    returned.
 	 */
-	virtual TermList * open_synonym_keylist(const string & prefix) const;
+	virtual TermList * open_synonym_keylist(const std::string & prefix) const;
 
 	/** Add a synonym for a term.
 	 *
 	 *  If @a synonym is already a synonym for @a term, then no action is
 	 *  taken.
 	 */
-	virtual void add_synonym(const string & term, const string & synonym) const;
+	virtual void add_synonym(const std::string & term, const std::string & synonym) const;
 
 	/** Remove a synonym for a term.
 	 *
 	 *  If @a synonym isn't a synonym for @a term, then no action is taken.
 	 */
-	virtual void remove_synonym(const string & term, const string & synonym) const;
+	virtual void remove_synonym(const std::string & term, const std::string & synonym) const;
 
 	/** Clear all synonyms for a term.
 	 *
 	 *  If @a term has no synonyms, no action is taken.
 	 */
-	virtual void clear_synonyms(const string & term) const;
+	virtual void clear_synonyms(const std::string & term) const;
 
 	/** Get the metadata associated with a given key.
 	 *
 	 *  See Database::get_metadata() for more information.
 	 */
-	virtual string get_metadata(const string & key) const;
+	virtual std::string get_metadata(const std::string & key) const;
 
 	/** Open a termlist returning each metadata key.
 	 *
@@ -380,7 +380,7 @@
 	 *
 	 *  See WritableDatabase::set_metadata() for more information.
 	 */
-	virtual void set_metadata(const string & key, const string & value);
+	virtual void set_metadata(const std::string & key, const std::string & value);
 
 	/** Reopen the database to the latest available revision.
 	 *
@@ -440,7 +440,7 @@
 	 *
 	 *  See WritableDatabase::delete_document() for more information.
 	 */
-	virtual void delete_document(const string & unique_term);
+	virtual void delete_document(const std::string & unique_term);
 
 	/** Replace a given document in the database.
 	 *
@@ -453,7 +453,7 @@
 	 *
 	 *  See WritableDatabase::replace_document() for more information.
 	 */
-	virtual Xapian::docid replace_document(const string & unique_term,
+	virtual Xapian::docid replace_document(const std::string & unique_term,
 					       const Xapian::Document & document);
 
 	/** Request and later collect a document from the database.
@@ -481,8 +481,8 @@
 					    bool need_whole_db,
 					    Xapian::ReplicationInfo * info);
 
-	/// Get a string describing the current revision of the database.
-	virtual string get_revision_info() const;
+	/// Get a std::string describing the current revision of the database.
+	virtual std::string get_revision_info() const;
 
 	/** Get a UUID for the database.
 	 *
@@ -492,9 +492,9 @@
 	 *  the database files) will have the same UUID.  However, copies (made
 	 *  with copydatabase, or xapian-compact) will have different UUIDs.
 	 *
-	 *  If the backend does not support UUIDs the empty string is returned.
+	 *  If the backend does not support UUIDs the empty std::string is returned.
 	 */
-	virtual string get_uuid() const;
+	virtual std::string get_uuid() const;
 
 	/** Notify the database that document is no longer valid.
 	 *
@@ -507,8 +507,8 @@
 
 	/** Get backend information about this database.
 	 *
-	 *  @param path  If non-NULL, and set the pointed to string to the file
-	 *		 path of this database (or if to some string describing
+	 *  @param path  If non-NULL, and set the pointed to std::string to the file
+	 *		 path of this database (or if to some std::string describing
 	 *		 the database in a backend-specified format if "path"
 	 *		 isn't a concept which  make sense).
 	 *
diff -ur xapian-core-1.4.21/backends/databasereplicator.cc xapian-core-1.4.21/backends/databasereplicator.cc
--- xapian-core-1.4.21/backends/databasereplicator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/databasereplicator.cc	2022-11-08 16:44:15.348461970 +0100
@@ -46,7 +46,7 @@
 }
 
 DatabaseReplicator *
-DatabaseReplicator::open(const string & path)
+DatabaseReplicator::open(const std::string & path)
 {
     LOGCALL_STATIC(DB, DatabaseReplicator *, "DatabaseReplicator::open", path);
 
diff -ur xapian-core-1.4.21/backends/dbcheck.cc xapian-core-1.4.21/backends/dbcheck.cc
--- xapian-core-1.4.21/backends/dbcheck.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/dbcheck.cc	2022-11-08 16:44:15.340461999 +0100
@@ -98,7 +98,7 @@
 #endif
 
 static size_t
-check_db_dir(const string & path, int opts, std::ostream *out)
+check_db_dir(const std::string & path, int opts, std::ostream *out)
 {
     struct stat sb;
     if (stat((path + "/iamchert").c_str(), &sb) == 0) {
@@ -156,7 +156,7 @@
 		*out << name << ":\n";
 	    if (strcmp(name, "record") != 0 && strcmp(name, "postlist") != 0) {
 		// Other tables are created lazily, so may not exist.
-		string table(path);
+		std::string table(path);
 		table += '/';
 		table += name;
 		table += ".DB";
@@ -214,7 +214,7 @@
 	GlassVersion version_file(path);
 	version_file.read();
 	for (glass_revision_number_t r = version_file.get_revision(); r != 0; --r) {
-	    string changes_file = path;
+	    std::string changes_file = path;
 	    changes_file += "/changes";
 	    changes_file += str(r);
 	    if (file_exists(changes_file))
@@ -275,9 +275,9 @@
     // want.
     ++p;
 
-    string dir(filename, 0, p);
+    std::string dir(filename, 0, p);
 
-    string tablename;
+    std::string tablename;
     while (p != filename.size()) {
 	char ch = filename[p++];
 	if (ch == '.') break;
@@ -285,7 +285,7 @@
     }
 
 #if defined XAPIAN_HAS_CHERT_BACKEND || defined XAPIAN_HAS_GLASS_BACKEND
-    vector<Xapian::termcount> doclens;
+    std::vector<Xapian::termcount> doclens;
 #else
     (void)opts;
     (void)out;
@@ -419,7 +419,7 @@
 }
 
 size_t
-Database::check_(const string * path_ptr, int fd, int opts, std::ostream *out)
+Database::check_(const std::string * path_ptr, int fd, int opts, std::ostream *out)
 {
     if (!out) {
 	// If we have nowhere to write output, then disable all the options
@@ -431,7 +431,7 @@
 	return check_db_fd(fd, opts, out, BACKEND_UNKNOWN);
     }
 
-    const string & path = *path_ptr;
+    const std::string & path = *path_ptr;
     struct stat sb;
     if (stat(path.c_str(), &sb) == 0) {
 	if (S_ISDIR(sb.st_mode)) {
@@ -464,7 +464,7 @@
     // table (perhaps with "." after it), so the user can do xapian-check on
     // "foo/termlist" or "foo/termlist." (which you would get from filename
     // completion with older backends).
-    string filename = path;
+    std::string filename = path;
     if (endswith(filename, '.')) {
 	filename.resize(filename.size() - 1);
     }
diff -ur xapian-core-1.4.21/backends/dbfactory.cc xapian-core-1.4.21/backends/dbfactory.cc
--- xapian-core-1.4.21/backends/dbfactory.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/dbfactory.cc	2022-11-08 16:44:15.328462041 +0100
@@ -153,7 +153,7 @@
     }
 }
 
-Database::Database(const string &path, int flags)
+Database::Database(const std::string &path, int flags)
 {
     LOGCALL_CTOR(API, "Database", path|flags);
 
@@ -233,7 +233,7 @@
 #endif
 
     // Check for "stub directories".
-    string stub_file = path;
+    std::string stub_file = path;
     stub_file += "/XAPIANDB";
     if (usual(file_exists(stub_file))) {
 	open_stub(*this, stub_file);
@@ -330,7 +330,7 @@
 		throw FeatureUnavailableError("Flint backend no longer supported");
 	    } else {
 		// Check for "stub directories".
-		string stub_file = path;
+		std::string stub_file = path;
 		stub_file += "/XAPIANDB";
 		if (usual(file_exists(stub_file))) {
 		    open_stub(*this, stub_file, flags);
diff -ur xapian-core-1.4.21/backends/dbfactory_remote.cc xapian-core-1.4.21/backends/dbfactory_remote.cc
--- xapian-core-1.4.21/backends/dbfactory_remote.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/dbfactory_remote.cc	2022-11-08 16:44:15.416461728 +0100
@@ -39,7 +39,7 @@
 #endif
 
 Database
-Remote::open(const string &host, unsigned int port, useconds_t timeout_,
+Remote::open(const std::string &host, unsigned int port, useconds_t timeout_,
 	     useconds_t connect_timeout)
 {
     LOGCALL_STATIC(API, Database, "Remote::open", host | port | timeout_ | connect_timeout);
@@ -48,7 +48,7 @@
 }
 
 WritableDatabase
-Remote::open_writable(const string &host, unsigned int port,
+Remote::open_writable(const std::string &host, unsigned int port,
 		      useconds_t timeout_, useconds_t connect_timeout,
 		      int flags)
 {
@@ -59,7 +59,7 @@
 }
 
 Database
-Remote::open(const string &program, const string &args,
+Remote::open(const std::string &program, const std::string &args,
 	     useconds_t timeout_)
 {
     LOGCALL_STATIC(API, Database, "Remote::open", program | args | timeout_);
@@ -67,7 +67,7 @@
 }
 
 WritableDatabase
-Remote::open_writable(const string &program, const string &args,
+Remote::open_writable(const std::string &program, const std::string &args,
 		      useconds_t timeout_, int flags)
 {
     LOGCALL_STATIC(API, WritableDatabase, "Remote::open_writable", program | args | timeout_ | flags);
diff -ur xapian-core-1.4.21/backends/document.h xapian-core-1.4.21/backends/document.h
--- xapian-core-1.4.21/backends/document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/document.h	2022-11-08 16:44:00.912513288 +0100
@@ -32,7 +32,7 @@
 #include <map>
 #include <string>
 
-using namespace std;
+using std::string;
 
 class DocumentValueList;
 class ValueStreamDocument;
@@ -43,10 +43,10 @@
     friend class ::ValueStreamDocument;
     public:
 	/// Type to store values in.
-	typedef map<Xapian::valueno, string> document_values;
+	typedef std::map<Xapian::valueno, string> document_values;
 
 	/// Type to store terms in.
-	typedef map<string, OmDocumentTerm> document_terms;
+	typedef std::map<string, OmDocumentTerm> document_terms;
 
     protected:
 	/// The database this document is in.
@@ -63,7 +63,7 @@
 	mutable bool positions_modified;
 
 	/// The (user defined) data associated with this document.
-	string data;
+	std::string data;
 
 	/// The values associated with this document.
 	mutable document_values values; // FIXME mutable is a hack
@@ -89,11 +89,11 @@
 
     private:
 	// Functions for backend to implement
-	virtual string do_get_value(Xapian::valueno /*valueno*/) const { return string(); }
-	virtual void do_get_all_values(map<Xapian::valueno, string> & values_) const {
+	virtual std::string do_get_value(Xapian::valueno /*valueno*/) const { return string(); }
+	virtual void do_get_all_values(std::map<Xapian::valueno, string> & values_) const {
 	    values_.clear();
 	}
-	virtual string do_get_data() const { return string(); }
+	virtual std::string do_get_data() const { return string(); }
 
     public:
 	/** Get value by value number.
@@ -108,34 +108,34 @@
 	 *
 	 *  @param slot  The value number requested.
 	 *
-	 *  @return       A string containing the specified value.  If
+	 *  @return       A std::string containing the specified value.  If
 	 *  the value is not present in this document, the value's value will
 	 *  be a zero length string
 	 */
-	string get_value(Xapian::valueno slot) const;
+	std::string get_value(Xapian::valueno slot) const;
 
 	/** Set all the values.
 	 *
 	 *  @param values_	The values to set - passed by non-const reference, and
 	 *			may be modified by the call.
 	 */
-	void set_all_values(map<Xapian::valueno, string> & values_) {
+	void set_all_values(std::map<Xapian::valueno, string> & values_) {
 	    // For efficiency we just swap the old and new value maps.
 	    swap(values, values_);
 	    values_here = true;
 	}
 
 	Xapian::valueno values_count() const;
-	void add_value(Xapian::valueno, const string &);
+	void add_value(Xapian::valueno, const std::string &);
 	void remove_value(Xapian::valueno);
 	void clear_values();
-	void add_posting(const string &, Xapian::termpos, Xapian::termcount);
-	void add_term(const string &, Xapian::termcount);
-	void remove_posting(const string &, Xapian::termpos, Xapian::termcount);
-	Xapian::termpos remove_postings(const string &,
+	void add_posting(const std::string &, Xapian::termpos, Xapian::termcount);
+	void add_term(const std::string &, Xapian::termcount);
+	void remove_posting(const std::string &, Xapian::termpos, Xapian::termcount);
+	Xapian::termpos remove_postings(const std::string &,
 					Xapian::termpos, Xapian::termpos,
 					Xapian::termcount);
-	void remove_term(const string &);
+	void remove_term(const std::string &);
 	void clear_terms();
 	Xapian::termcount termlist_count() const;
 
@@ -150,11 +150,11 @@
 	 *  during the match operation (such as in a match decider functor):
 	 *  use a value instead, if at all possible.
 	 *
-	 *  @return       A string containing the data for this document.
+	 *  @return       A std::string containing the data for this document.
 	 */
-	string get_data() const;
+	std::string get_data() const;
 
-	void set_data(const string &);
+	void set_data(const std::string &);
 
 	/** Open a term list.
 	 *
@@ -208,8 +208,8 @@
 	 */
 	Xapian::docid get_docid() const { return did; }
 
-	/// Return a string describing this object.
-	string get_description() const;
+	/// Return a std::string describing this object.
+	std::string get_description() const;
 
 	/** Constructor.
 	 *
diff -ur xapian-core-1.4.21/backends/flint_lock.cc xapian-core-1.4.21/backends/flint_lock.cc
--- xapian-core-1.4.21/backends/flint_lock.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/flint_lock.cc	2022-11-08 16:44:15.336462012 +0100
@@ -122,7 +122,7 @@
 }
 
 FlintLock::reason
-FlintLock::lock(bool exclusive, bool wait, string & explanation) {
+FlintLock::lock(bool exclusive, bool wait, std::string & explanation) {
     // Currently we only support exclusive locks.
     (void)exclusive;
     Assert(exclusive);
@@ -497,10 +497,10 @@
 
 void
 FlintLock::throw_databaselockerror(FlintLock::reason why,
-				   const string & db_dir,
-				   const string & explanation) const
+				   const std::string & db_dir,
+				   const std::string & explanation) const
 {
-    string msg("Unable to get write lock on ");
+    std::string msg("Unable to get write lock on ");
     msg += db_dir;
     if (why == FlintLock::INUSE) {
 	msg += ": already locked";
diff -ur xapian-core-1.4.21/backends/flint_lock.h xapian-core-1.4.21/backends/flint_lock.h
--- xapian-core-1.4.21/backends/flint_lock.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/flint_lock.h	2022-11-08 16:44:00.944513174 +0100
@@ -93,7 +93,7 @@
 
     /** Attempt to obtain the lock.
      *
-     *  If the attempt fails with code "UNKNOWN", the string supplied in the
+     *  If the attempt fails with code "UNKNOWN", the std::string supplied in the
      *  explanation parameter will be set to contain any details available of
      *  the reason for the failure.
      *
diff -ur xapian-core-1.4.21/backends/glass/glass_alldocspostlist.cc xapian-core-1.4.21/backends/glass/glass_alldocspostlist.cc
--- xapian-core-1.4.21/backends/glass/glass_alldocspostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_alldocspostlist.cc	2022-11-08 16:44:15.376461870 +0100
@@ -80,7 +80,7 @@
 string
 GlassAllDocsPostList::get_description() const
 {
-    string desc = "GlassAllDocsPostList(doccount=";
+    std::string desc = "GlassAllDocsPostList(doccount=";
     desc += str(doccount);
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/backends/glass/glass_alltermslist.cc xapian-core-1.4.21/backends/glass/glass_alltermslist.cc
--- xapian-core-1.4.21/backends/glass/glass_alltermslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_alltermslist.cc	2022-11-08 16:44:15.372461885 +0100
@@ -83,7 +83,7 @@
 	if (prefix.empty()) {
 	    (void)cursor->find_entry_ge(string("\x00\xff", 2));
 	} else {
-	    const string & key = pack_glass_postlist_key(prefix);
+	    const std::string & key = pack_glass_postlist_key(prefix);
 	    if (cursor->find_entry_ge(key)) {
 		// The exact term we asked for is there, so just copy it rather
 		// than wasting effort unpacking it from the key.
@@ -124,7 +124,7 @@
 }
 
 TermList *
-GlassAllTermsList::skip_to(const string &term)
+GlassAllTermsList::skip_to(const std::string &term)
 {
     LOGCALL(DB, TermList *, "GlassAllTermsList::skip_to", term);
     Assert(!at_end());
@@ -137,7 +137,7 @@
 	Assert(cursor); // The postlist table isn't optional.
     }
 
-    string key = pack_glass_postlist_key(term);
+    std::string key = pack_glass_postlist_key(term);
     if (cursor->find_entry_ge(key)) {
 	// The exact term we asked for is there, so just copy it rather than
 	// wasting effort unpacking it from the key.
diff -ur xapian-core-1.4.21/backends/glass/glass_changes.cc xapian-core-1.4.21/backends/glass/glass_changes.cc
--- xapian-core-1.4.21/backends/glass/glass_changes.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_changes.cc	2022-11-08 16:44:15.356461942 +0100
@@ -44,7 +44,7 @@
 {
     if (changes_fd >= 0) {
 	::close(changes_fd);
-	string changes_tmp = changes_stem;
+	std::string changes_tmp = changes_stem;
 	changes_tmp += "tmp";
 	io_unlink(changes_tmp);
     }
@@ -71,19 +71,19 @@
     if (max_changesets == 0)
 	return NULL;
 
-    string changes_tmp = changes_stem;
+    std::string changes_tmp = changes_stem;
     changes_tmp += "tmp";
     changes_fd = posixy_open(changes_tmp.c_str(),
 			     O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0666);
     if (changes_fd < 0) {
-	string message = "Couldn't open changeset ";
+	std::string message = "Couldn't open changeset ";
 	message += changes_tmp;
 	message += " to write";
 	throw Xapian::DatabaseError(message, errno);
     }
 
     // Write header for changeset file.
-    string header = CHANGES_MAGIC_STRING;
+    std::string header = CHANGES_MAGIC_STRING;
     header += char(CHANGES_VERSION);
     pack_uint(header, old_rev);
     pack_uint(header, rev);
@@ -115,7 +115,7 @@
 
     io_write(changes_fd, "\xff", 1);
 
-    string changes_tmp = changes_stem;
+    std::string changes_tmp = changes_stem;
     changes_tmp += "tmp";
 
     if (!(flags & Xapian::DB_NO_SYNC) && !io_sync(changes_fd)) {
@@ -123,7 +123,7 @@
 	(void)::close(changes_fd);
 	changes_fd = -1;
 	(void)unlink(changes_tmp.c_str());
-	string m = changes_tmp;
+	std::string m = changes_tmp;
 	m += ": Failed to sync";
 	throw Xapian::DatabaseError(m, saved_errno);
     }
@@ -131,11 +131,11 @@
     (void)::close(changes_fd);
     changes_fd = -1;
 
-    string changes_file = changes_stem;
+    std::string changes_file = changes_stem;
     changes_file += str(new_rev - 1); // FIXME: ?
 
     if (!io_tmp_rename(changes_tmp, changes_file)) {
-	string m = changes_tmp;
+	std::string m = changes_tmp;
 	m += ": Failed to rename to ";
 	m += changes_file;
 	throw Xapian::DatabaseError(m, errno);
@@ -161,11 +161,11 @@
 }
 
 void
-GlassChanges::check(const string & changes_file)
+GlassChanges::check(const std::string & changes_file)
 {
     FD fd(posixy_open(changes_file.c_str(), O_RDONLY | O_CLOEXEC, 0666));
     if (fd < 0) {
-	string message = "Couldn't open changeset ";
+	std::string message = "Couldn't open changeset ";
 	message += changes_file;
 	throw Xapian::DatabaseError(message, errno);
     }
diff -ur xapian-core-1.4.21/backends/glass/glass_check.cc xapian-core-1.4.21/backends/glass/glass_check.cc
--- xapian-core-1.4.21/backends/glass/glass_check.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_check.cc	2022-11-08 16:44:15.356461942 +0100
@@ -51,10 +51,10 @@
 {
     if (j == 0) {
 	LeafItem item(p, c);
-	string key;
+	std::string key;
 	if (item.key().length() >= 0)
 	    item.key().read(&key);
-	string escaped;
+	std::string escaped;
 	description_append(escaped, key);
 	*out << escaped;
 	int x = item.component_of();
@@ -64,10 +64,10 @@
 	}
     } else {
 	BItem item(p, c);
-	string key;
+	std::string key;
 	if (item.key().length() >= 0)
 	    item.key().read(&key);
-	string escaped;
+	std::string escaped;
 	description_append(escaped, key);
 	*out << escaped;
     }
@@ -77,9 +77,9 @@
 {
     if (j == 0) {
 	LeafItem item(p, c);
-	string tag;
+	std::string tag;
 	item.append_chunk(&tag);
-	string escaped;
+	std::string escaped;
 	description_append(escaped, tag);
 	*out << ' ' << escaped;
     } else {
@@ -141,7 +141,7 @@
 static void
 failure(const char *msg, uint4 n, int c)
 {
-    string e = "Block ";
+    std::string e = "Block ";
     e += str(n);
     if (c) {
 	e += " item ";
@@ -260,12 +260,12 @@
 }
 
 GlassTableCheck *
-GlassTableCheck::check(const char * tablename, const string & path, int fd,
+GlassTableCheck::check(const char * tablename, const std::string & path, int fd,
 		       off_t offset_,
 		       const GlassVersion & version_file, int opts,
 		       ostream *out)
 {
-    string filename(path);
+    std::string filename(path);
     filename += '/';
     filename += tablename;
     filename += '.';
@@ -289,7 +289,7 @@
     } else if (strcmp(tablename, "synonym") == 0) {
 	tab_type = Glass::SYNONYM;
     } else {
-	string e = "Unknown table: ";
+	std::string e = "Unknown table: ";
 	e += tablename;
 	throw Xapian::DatabaseError(e);
     }
@@ -349,7 +349,7 @@
 	uint4 count = flcheck.count_set_bits(&first_bad);
 	// Skip this check for a single file DB for now.  FIXME
 	if (count && fd < 0) {
-	    string e = str(count);
+	    std::string e = str(count);
 	    e += " unused block(s) missing from the free list, first is ";
 	    e += str(first_bad);
 	    throw Xapian::DatabaseError(e);
diff -ur xapian-core-1.4.21/backends/glass/glass_compact.cc xapian-core-1.4.21/backends/glass/glass_compact.cc
--- xapian-core-1.4.21/backends/glass/glass_compact.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_compact.cc	2022-11-08 16:44:15.352461955 +0100
@@ -54,25 +54,25 @@
 namespace GlassCompact {
 
 static inline bool
-is_user_metadata_key(const string & key)
+is_user_metadata_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xc0';
 }
 
 static inline bool
-is_valuestats_key(const string & key)
+is_valuestats_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xd0';
 }
 
 static inline bool
-is_valuechunk_key(const string & key)
+is_valuechunk_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xd8';
 }
 
 static inline bool
-is_doclenchunk_key(const string & key)
+is_doclenchunk_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xe0';
 }
@@ -81,7 +81,7 @@
     Xapian::docid offset;
 
   public:
-    string key, tag;
+    std::string key, tag;
     Xapian::docid firstdid;
     Xapian::termcount tf, cf;
 
@@ -128,7 +128,7 @@
 	if (is_doclenchunk_key(key)) {
 	    d += 2;
 	} else {
-	    string tname;
+	    std::string tname;
 	    if (!unpack_string_preserving_sort(&d, e, tname))
 		throw Xapian::DatabaseCorruptError("Bad postlist key");
 	}
@@ -173,9 +173,9 @@
 
 static string
 encode_valuestats(Xapian::doccount freq,
-		  const string & lbound, const string & ubound)
+		  const std::string & lbound, const std::string & ubound)
 {
-    string value;
+    std::string value;
     pack_uint(value, freq);
     pack_string(value, lbound);
     // We don't store or count empty values, so neither of the bounds
@@ -187,11 +187,11 @@
 
 static void
 merge_postlists(Xapian::Compactor * compactor,
-		GlassTable * out, vector<Xapian::docid>::const_iterator offset,
+		GlassTable * out, std::vector<Xapian::docid>::const_iterator offset,
 		vector<GlassTable*>::const_iterator b,
 		vector<GlassTable*>::const_iterator e)
 {
-    priority_queue<PostlistCursor *, vector<PostlistCursor *>, PostlistCursorGt> pq;
+    priority_queue<PostlistCursor *, std::vector<PostlistCursor *>, PostlistCursorGt> pq;
     for ( ; b != e; ++b, ++offset) {
 	GlassTable *in = *b;
 	if (in->empty()) {
@@ -202,7 +202,7 @@
 	pq.push(new PostlistCursor(in, *offset));
     }
 
-    string last_key;
+    std::string last_key;
     {
 	// Merge user metadata.
 	vector<string> tags;
@@ -218,7 +218,7 @@
 			// FIXME: It would be better to merge all duplicates
 			// for a key in one call, but currently we don't in
 			// multipass mode.
-			const string & resolved_tag =
+			const std::string & resolved_tag =
 			    compactor->resolve_duplicate_metadata(last_key,
 								  tags.size(),
 								  &tags[0]);
@@ -244,7 +244,7 @@
 	if (!tags.empty()) {
 	    if (tags.size() > 1 && compactor) {
 		Assert(!last_key.empty());
-		const string & resolved_tag =
+		const std::string & resolved_tag =
 		    compactor->resolve_duplicate_metadata(last_key,
 							  tags.size(),
 							  &tags[0]);
@@ -260,7 +260,7 @@
     {
 	// Merge valuestats.
 	Xapian::doccount freq = 0;
-	string lbound, ubound;
+	std::string lbound, ubound;
 
 	while (!pq.empty()) {
 	    PostlistCursor * cur = pq.top();
@@ -277,13 +277,13 @@
 		last_key = key;
 	    }
 
-	    const string & tag = cur->tag;
+	    const std::string & tag = cur->tag;
 
 	    const char * pos = tag.data();
 	    const char * end = pos + tag.size();
 
 	    Xapian::doccount f;
-	    string l, u;
+	    std::string l, u;
 	    if (!unpack_uint(&pos, end, &f)) {
 		if (*pos == 0) throw Xapian::DatabaseCorruptError("Incomplete stats item in value table");
 		throw Xapian::RangeError("Frequency statistic in value table is too large");
@@ -324,7 +324,7 @@
     // Merge valuestream chunks.
     while (!pq.empty()) {
 	PostlistCursor * cur = pq.top();
-	const string & key = cur->key;
+	const std::string & key = cur->key;
 	if (!is_valuechunk_key(key)) break;
 	Assert(!is_user_metadata_key(key));
 	out->add(key, cur->tag);
@@ -337,7 +337,7 @@
     }
 
     Xapian::termcount tf = 0, cf = 0; // Initialise to avoid warnings.
-    vector<pair<Xapian::docid, string>> tags;
+    std::vector<pair<Xapian::docid, string>> tags;
     while (true) {
 	PostlistCursor * cur = NULL;
 	if (!pq.empty()) {
@@ -347,16 +347,16 @@
 	Assert(cur == NULL || !is_user_metadata_key(cur->key));
 	if (cur == NULL || cur->key != last_key) {
 	    if (!tags.empty()) {
-		string first_tag;
+		std::string first_tag;
 		pack_uint(first_tag, tf);
 		pack_uint(first_tag, cf);
 		pack_uint(first_tag, tags[0].first - 1);
-		string tag = tags[0].second;
+		std::string tag = tags[0].second;
 		tag[0] = (tags.size() == 1) ? '1' : '0';
 		first_tag += tag;
 		out->add(last_key, first_tag);
 
-		string term;
+		std::string term;
 		if (!is_doclenchunk_key(last_key)) {
 		    const char * p = last_key.data();
 		    const char * end = p + last_key.size();
@@ -408,7 +408,7 @@
 		vector<GlassTable*>::const_iterator b,
 		vector<GlassTable*>::const_iterator e)
 {
-    priority_queue<MergeCursor *, vector<MergeCursor *>, CursorGt> pq;
+    priority_queue<MergeCursor *, std::vector<MergeCursor *>, CursorGt> pq;
     for ( ; b != e; ++b) {
 	GlassTable *in = *b;
 	if (!in->empty()) {
@@ -420,7 +420,7 @@
 	MergeCursor * cur = pq.top();
 	pq.pop();
 
-	string key = cur->current_key;
+	std::string key = cur->current_key;
 	if (pq.empty() || pq.top()->current_key > key) {
 	    // No need to merge the tags, just copy the (possibly compressed)
 	    // tag value.
@@ -435,17 +435,17 @@
 	}
 
 	// Merge tag values with the same key:
-	string tag;
+	std::string tag;
 	if (key[0] != 'W') {
 	    // We just want the union of words, so copy over the first instance
 	    // and skip any identical ones.
 	    priority_queue<PrefixCompressedStringItor *,
-			   vector<PrefixCompressedStringItor *>,
+			   std::vector<PrefixCompressedStringItor *>,
 			   PrefixCompressedStringItorGt> pqtag;
 	    // Stick all the MergeCursor pointers in a vector because their
 	    // current_tag members must remain valid while we're merging their
 	    // tags, but we need to call next() on them all afterwards.
-	    vector<MergeCursor *> vec;
+	    std::vector<MergeCursor *> vec;
 	    vec.reserve(pq.size());
 
 	    while (true) {
@@ -458,11 +458,11 @@
 	    }
 
 	    PrefixCompressedStringWriter wr(tag);
-	    string lastword;
+	    std::string lastword;
 	    while (!pqtag.empty()) {
 		PrefixCompressedStringItor * it = pqtag.top();
 		pqtag.pop();
-		string word = **it;
+		std::string word = **it;
 		if (word != lastword) {
 		    lastword = word;
 		    wr.append(lastword);
@@ -475,7 +475,7 @@
 		}
 	    }
 
-	    vector<MergeCursor *>::const_iterator i;
+	    std::vector<MergeCursor *>::const_iterator i;
 	    for (i = vec.begin(); i != vec.end(); ++i) {
 		cur = *i;
 		if (cur->next()) {
@@ -514,10 +514,10 @@
 
 static void
 merge_synonyms(GlassTable * out,
-	       vector<GlassTable*>::const_iterator b,
-	       vector<GlassTable*>::const_iterator e)
+	       std::vector<GlassTable*>::const_iterator b,
+	       std::vector<GlassTable*>::const_iterator e)
 {
-    priority_queue<MergeCursor *, vector<MergeCursor *>, CursorGt> pq;
+    priority_queue<MergeCursor *, std::vector<MergeCursor *>, CursorGt> pq;
     for ( ; b != e; ++b) {
 	GlassTable *in = *b;
 	if (!in->empty()) {
@@ -529,7 +529,7 @@
 	MergeCursor * cur = pq.top();
 	pq.pop();
 
-	string key = cur->current_key;
+	std::string key = cur->current_key;
 	if (pq.empty() || pq.top()->current_key > key) {
 	    // No need to merge the tags, just copy the (possibly compressed)
 	    // tag value.
@@ -544,12 +544,12 @@
 	}
 
 	// Merge tag values with the same key:
-	string tag;
+	std::string tag;
 
 	// We just want the union of words, so copy over the first instance
 	// and skip any identical ones.
 	priority_queue<ByteLengthPrefixedStringItor *,
-		       vector<ByteLengthPrefixedStringItor *>,
+		       std::vector<ByteLengthPrefixedStringItor *>,
 		       ByteLengthPrefixedStringItorGt> pqtag;
 	vector<MergeCursor *> vec;
 
@@ -562,7 +562,7 @@
 	    pq.pop();
 	}
 
-	string lastword;
+	std::string lastword;
 	while (!pqtag.empty()) {
 	    ByteLengthPrefixedStringItor * it = pqtag.top();
 	    pqtag.pop();
@@ -596,8 +596,8 @@
 static void
 multimerge_postlists(Xapian::Compactor * compactor,
 		     GlassTable * out, const char * tmpdir,
-		     vector<GlassTable *> tmp,
-		     vector<Xapian::docid> off)
+		     std::vector<GlassTable *> tmp,
+		     std::vector<Xapian::docid> off)
 {
     unsigned int c = 0;
     while (tmp.size() > 3) {
@@ -609,7 +609,7 @@
 	    j = i + 2;
 	    if (j == tmp.size() - 1) ++j;
 
-	    string dest = tmpdir;
+	    std::string dest = tmpdir;
 	    char buf[64];
 	    sprintf(buf, "/tmp%u_%u.", c, i / 2);
 	    dest += buf;
@@ -657,7 +657,7 @@
     Xapian::docid offset;
 
   public:
-    string key;
+    std::string key;
     Xapian::docid firstdid;
 
     PositionCursor(GlassTable *in, Xapian::docid offset_)
@@ -671,7 +671,7 @@
 	read_tag();
 	const char * d = current_key.data();
 	const char * e = d + current_key.size();
-	string term;
+	std::string term;
 	Xapian::docid did;
 	if (!unpack_string_preserving_sort(&d, e, term) ||
 	    !unpack_uint_preserving_sort(&d, e, &did) ||
@@ -685,7 +685,7 @@
 	return true;
     }
 
-    const string & get_tag() const {
+    const std::string & get_tag() const {
 	return current_tag;
     }
 };
@@ -700,10 +700,10 @@
 };
 
 static void
-merge_positions(GlassTable *out, const vector<GlassTable*> & inputs,
-		const vector<Xapian::docid> & offset)
+merge_positions(GlassTable *out, const std::vector<GlassTable*> & inputs,
+		const std::vector<Xapian::docid> & offset)
 {
-    priority_queue<PositionCursor *, vector<PositionCursor *>, PositionCursorGt> pq;
+    priority_queue<PositionCursor *, std::vector<PositionCursor *>, PositionCursorGt> pq;
     for (size_t i = 0; i < inputs.size(); ++i) {
 	GlassTable *in = inputs[i];
 	if (in->empty()) {
@@ -727,8 +727,8 @@
 }
 
 static void
-merge_docid_keyed(GlassTable *out, const vector<GlassTable*> & inputs,
-		  const vector<Xapian::docid> & offset)
+merge_docid_keyed(GlassTable *out, const std::vector<GlassTable*> & inputs,
+		  const std::vector<Xapian::docid> & offset)
 {
     for (size_t i = 0; i < inputs.size(); ++i) {
 	Xapian::docid off = offset[i];
@@ -739,7 +739,7 @@
 	GlassCursor cur(in);
 	cur.find_entry(string());
 
-	string key;
+	std::string key;
 	while (cur.next()) {
 	    // Adjust the key if this isn't the first database.
 	    if (off) {
@@ -747,7 +747,7 @@
 		const char * d = cur.current_key.data();
 		const char * e = d + cur.current_key.size();
 		if (!unpack_uint_preserving_sort(&d, e, &did)) {
-		    string msg = "Bad key in ";
+		    std::string msg = "Bad key in ";
 		    msg += inputs[i]->get_path();
 		    throw Xapian::DatabaseCorruptError(msg);
 		}
@@ -776,8 +776,8 @@
 GlassDatabase::compact(Xapian::Compactor * compactor,
 		       const char * destdir,
 		       int fd,
-		       const vector<Xapian::Database::Internal*> & sources,
-		       const vector<Xapian::docid> & offset,
+		       const std::vector<Xapian::Database::Internal*> & sources,
+		       const std::vector<Xapian::docid> & offset,
 		       size_t block_size,
 		       Xapian::Compactor::compaction_level compaction,
 		       unsigned flags,
@@ -832,7 +832,7 @@
 
     FlintLock lock(destdir ? destdir : "");
     if (!single_file) {
-	string explanation;
+	std::string explanation;
 	FlintLock::reason why = lock.lock(true, false, explanation);
 	if (why != FlintLock::SUCCESS) {
 	    lock.throw_databaselockerror(why, destdir, explanation);
@@ -859,14 +859,14 @@
 	version_file_out->merge_stats(db->version_file);
     }
 
-    string fl_serialised;
+    std::string fl_serialised;
     if (single_file) {
 	GlassFreeList fl;
 	fl.set_first_unused_block(1); // FIXME: Assumption?
 	fl.pack(fl_serialised);
     }
 
-    vector<GlassTable *> tabs;
+    std::vector<GlassTable *> tabs;
     tabs.reserve(tables_end - tables);
     off_t prev_size = block_size;
     for (const table_list * t = tables; t < tables_end; ++t) {
@@ -878,7 +878,7 @@
 	if (compactor)
 	    compactor->set_status(t->name, string());
 
-	string dest;
+	std::string dest;
 	if (!single_file) {
 	    dest = destdir;
 	    dest += '/';
@@ -958,7 +958,7 @@
 	if (t->type == Glass::TERMLIST && inputs_present != sources.size()) {
 	    if (inputs_present != 0) {
 		if (compactor) {
-		    string m = str(inputs_present);
+		    std::string m = str(inputs_present);
 		    m += " of ";
 		    m += str(sources.size());
 		    m += " inputs present, so suppressing output";
@@ -1052,7 +1052,7 @@
 	    if (compactor)
 		compactor->set_status(t->name, "Done (table sizes unknown for single file DB input)");
 	} else {
-	    string status;
+	    std::string status;
 	    if (out_size == in_size) {
 		status = "Size unchanged (";
 	    } else {
@@ -1102,7 +1102,7 @@
 	}
     }
     version_file_out->set_last_docid(last_docid);
-    string tmpfile = version_file_out->write(1, FLAGS);
+    std::string tmpfile = version_file_out->write(1, FLAGS);
     for (unsigned j = 0; j != tabs.size(); ++j) {
 	tabs[j]->sync();
     }
diff -ur xapian-core-1.4.21/backends/glass/glass_cursor.cc xapian-core-1.4.21/backends/glass/glass_cursor.cc
--- xapian-core-1.4.21/backends/glass/glass_cursor.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_cursor.cc	2022-11-08 16:44:15.376461870 +0100
@@ -34,10 +34,10 @@
 
 #ifdef XAPIAN_DEBUG_LOG
 static string
-hex_display_encode(const string & input)
+hex_display_encode(const std::string & input)
 {
     const char * table = "0123456789abcdef";
-    string result;
+    std::string result;
     for (string::const_iterator i = input.begin(); i != input.end(); ++i) {
 	unsigned char val = *i;
 	result += "\\x";
@@ -141,7 +141,7 @@
 }
 
 bool
-GlassCursor::find_entry(const string &key)
+GlassCursor::find_entry(const std::string &key)
 {
     LOGCALL(DB, bool, "GlassCursor::find_entry", key);
     if (B->cursor_version != version) {
@@ -187,7 +187,7 @@
 }
 
 void
-GlassCursor::find_entry_lt(const string &key)
+GlassCursor::find_entry_lt(const std::string &key)
 {
     LOGCALL_VOID(DB, "GlassCursor::find_entry_lt", key);
     if (!find_entry(key)) {
@@ -210,7 +210,7 @@
 }
 
 bool
-GlassCursor::find_exact(const string &key)
+GlassCursor::find_exact(const std::string &key)
 {
     LOGCALL(DB, bool, "GlassCursor::find_exact", key);
     is_after_end = false;
@@ -235,7 +235,7 @@
 }
 
 bool
-GlassCursor::find_entry_ge(const string &key)
+GlassCursor::find_entry_ge(const std::string &key)
 {
     LOGCALL(DB, bool, "GlassCursor::find_entry_ge", key);
     if (B->cursor_version != version) {
diff -ur xapian-core-1.4.21/backends/glass/glass_cursor.h xapian-core-1.4.21/backends/glass/glass_cursor.h
--- xapian-core-1.4.21/backends/glass/glass_cursor.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_cursor.h	2022-11-08 16:44:00.936513203 +0100
@@ -195,7 +195,7 @@
      *  e.g.
      *
      *    GlassCursor BC(&btree);
-     *    string key;
+     *    std::string key;
      *
      *    // Now do something to each key in the Btree
      *    BC.find_entry(string()); // must give result true
@@ -236,12 +236,12 @@
 
     /** Current key pointed to by cursor.
      */
-    string current_key;
+    std::string current_key;
 
     /** Current tag pointed to by cursor.  You must call read_tag to
      *  make this value available.
      */
-    string current_tag;
+    std::string current_tag;
 
     /** Read the tag from the table and store it in current_tag.
      *
@@ -295,7 +295,7 @@
      *  @return true if the exact key was found in the table, false
      *          otherwise.
      */
-    bool find_entry(const string &key);
+    bool find_entry(const std::string &key);
 
     /** Position the cursor exactly on a key.
      *
@@ -305,17 +305,17 @@
      *  @param key	The key to search for.
      *  @return true if the key was found.
      */
-    bool find_exact(const string &key);
+    bool find_exact(const std::string &key);
 
     /// Position the cursor on the highest entry with key < @a key.
-    void find_entry_lt(const string &key);
+    void find_entry_lt(const std::string &key);
 
     /** Position the cursor on the lowest entry with key >= @a key.
      *
      *  @return true if the exact key was found in the table, false
      *          otherwise.
      */
-    bool find_entry_ge(const string &key);
+    bool find_entry_ge(const std::string &key);
 
     /** Set the cursor to be off the end of the table.
      */
diff -ur xapian-core-1.4.21/backends/glass/glass_database.cc xapian-core-1.4.21/backends/glass/glass_database.cc
--- xapian-core-1.4.21/backends/glass/glass_database.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_database.cc	2022-11-08 16:44:15.364461914 +0100
@@ -78,7 +78,7 @@
 
 // The maximum safe term length is determined by the postlist.  There we
 // store the term using pack_string_preserving_sort() which takes the
-// length of the string plus an extra byte (assuming the string doesn't
+// length of the std::string plus an extra byte (assuming the std::string doesn't
 // contain any zero bytes), followed by the docid with encoded with
 // pack_uint_preserving_sort() which takes up to 5 bytes (for a 32-bit
 // docid).
@@ -95,7 +95,7 @@
 /* This opens the tables, determining the current and next revision numbers,
  * and stores handles to the tables.
  */
-GlassDatabase::GlassDatabase(const string &glass_dir, int flags,
+GlassDatabase::GlassDatabase(const std::string &glass_dir, int flags,
 			     unsigned int block_size)
 	: db_dir(glass_dir),
 	  readonly(flags == Xapian::DB_READONLY_),
@@ -287,13 +287,13 @@
 }
 
 void
-GlassDatabase::get_changeset_revisions(const string & path,
+GlassDatabase::get_changeset_revisions(const std::string & path,
 				       glass_revision_number_t * startrev,
 				       glass_revision_number_t * endrev) const
 {
     FD fd(posixy_open(path.c_str(), O_RDONLY | O_CLOEXEC));
     if (fd < 0) {
-	string message = string("Couldn't open changeset ") +
+	std::string message = string("Couldn't open changeset ") +
 		path + " to read";
 	throw Xapian::DatabaseError(message, errno);
     }
@@ -305,7 +305,7 @@
 	throw Xapian::DatabaseError("Changeset too short at " + path);
     if (memcmp(start, CHANGES_MAGIC_STRING,
 	       CONST_STRLEN(CHANGES_MAGIC_STRING)) != 0) {
-	string message = string("Changeset at ") +
+	std::string message = string("Changeset at ") +
 		path + " does not contain valid magic string";
 	throw Xapian::DatabaseError(message);
     }
@@ -335,7 +335,7 @@
 
     glass_revision_number_t rev = version_file.get_revision();
     if (new_revision <= rev && rev != 0) {
-	string m = "New revision ";
+	std::string m = "New revision ";
 	m += str(new_revision);
 	m += " <= old revision ";
 	m += str(rev);
@@ -358,7 +358,7 @@
     spelling_table.commit(new_revision, version_file.root_to_set(Glass::SPELLING));
     docdata_table.commit(new_revision, version_file.root_to_set(Glass::DOCDATA));
 
-    const string & tmpfile = version_file.write(new_revision, flags);
+    const std::string & tmpfile = version_file.write(new_revision, flags);
     if (!postlist_table.sync() ||
 	!position_table.sync() ||
 	!termlist_table.sync() ||
@@ -385,7 +385,7 @@
 {
     Xapian::TermIterator t;
     for (t = query.get_unique_terms_begin(); t != Xapian::TermIterator(); ++t) {
-	const string & term = *t;
+	const std::string & term = *t;
 	if (!postlist_table.readahead_key(GlassPostListTable::make_key(term)))
 	    break;
     }
@@ -419,12 +419,12 @@
     // FIXME: Handle Xapian::DB_DANGEROUS here, perhaps by having readers
     // get a lock on the revision they're reading, and then requiring the
     // writer get an exclusive lock in this case.
-    string explanation;
+    std::string explanation;
     bool retry = flags & Xapian::DB_RETRY_LOCK;
     FlintLock::reason why = lock.lock(true, retry, explanation);
     if (why != FlintLock::SUCCESS) {
 	if (why == FlintLock::UNKNOWN && !creating && !database_exists()) {
-	    string msg("No glass database found at path '");
+	    std::string msg("No glass database found at path '");
 	    msg += db_dir;
 	    msg += '\'';
 	    throw Xapian::DatabaseNotFoundError(msg);
@@ -439,8 +439,8 @@
     LOGCALL_VOID(DB, "GlassDatabase::send_whole_database", conn | end_time);
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     // Send the current revision number in the header.
-    string buf;
-    string uuid = get_uuid();
+    std::string buf;
+    std::string uuid = get_uuid();
     buf += encode_length(uuid.size());
     buf += uuid;
     pack_uint(buf, get_revision_number());
@@ -456,7 +456,7 @@
 	"position." GLASS_TABLE_EXTENSION "\0"
 	"postlist." GLASS_TABLE_EXTENSION "\0"
 	"iamglass\0";
-    string filepath = db_dir;
+    std::string filepath = db_dir;
     filepath += '/';
     const char * p = filenames;
     do {
@@ -477,7 +477,7 @@
 
 void
 GlassDatabase::write_changesets_to_fd(int fd,
-				      const string & revision,
+				      const std::string & revision,
 				      bool need_whole_db,
 				      ReplicationInfo * info)
 {
@@ -485,7 +485,7 @@
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     int whole_db_copies_left = MAX_DB_COPIES_PER_CONVERSATION;
     glass_revision_number_t start_rev_num = 0;
-    string start_uuid = get_uuid();
+    std::string start_uuid = get_uuid();
 
     glass_revision_number_t needed_rev_num = 0;
 
@@ -532,7 +532,7 @@
 		// The update must proceed to that revision number before the
 		// copy is safe to make live.
 
-		string buf;
+		std::string buf;
 		needed_rev_num = get_revision_number();
 		pack_uint(buf, needed_rev_num);
 		conn.send_message(REPL_REPLY_DB_FOOTER, buf, 0.0);
@@ -547,7 +547,7 @@
 		// because the next message is going to be the start of a new
 		// database transfer.
 
-		string buf;
+		std::string buf;
 		pack_uint(buf, start_rev_num + 1);
 		conn.send_message(REPL_REPLY_DB_FOOTER, buf, 0.0);
 		need_whole_db = true;
@@ -566,7 +566,7 @@
 	    }
 
 	    // Look for the changeset for revision start_rev_num.
-	    string changes_name = db_dir + "/changes" + str(start_rev_num);
+	    std::string changes_name = db_dir + "/changes" + str(start_rev_num);
 	    FD fd_changes(posixy_open(changes_name.c_str(), O_RDONLY | O_CLOEXEC));
 	    if (fd_changes >= 0) {
 		// Send it, and also update start_rev_num to the new value
@@ -752,7 +752,7 @@
 }
 
 void
-GlassDatabase::get_freqs(const string & term,
+GlassDatabase::get_freqs(const std::string & term,
 			 Xapian::doccount * termfreq_ptr,
 			 Xapian::termcount * collfreq_ptr) const
 {
@@ -795,7 +795,7 @@
 }
 
 Xapian::termcount
-GlassDatabase::get_wdf_upper_bound(const string & term) const
+GlassDatabase::get_wdf_upper_bound(const std::string & term) const
 {
     Assert(!term.empty());
     Xapian::termcount wdfub;
@@ -804,7 +804,7 @@
 }
 
 bool
-GlassDatabase::term_exists(const string & term) const
+GlassDatabase::term_exists(const std::string & term) const
 {
     LOGCALL(DB, bool, "GlassDatabase::term_exists", term);
     Assert(!term.empty());
@@ -883,7 +883,7 @@
 }
 
 PositionList *
-GlassDatabase::open_position_list(Xapian::docid did, const string & term) const
+GlassDatabase::open_position_list(Xapian::docid did, const std::string & term) const
 {
     Assert(did != 0);
 
@@ -898,7 +898,7 @@
 }
 
 TermList *
-GlassDatabase::open_allterms(const string & prefix) const
+GlassDatabase::open_allterms(const std::string & prefix) const
 {
     LOGCALL(DB, TermList *, "GlassDatabase::open_allterms", NO_ARGS);
     RETURN(new GlassAllTermsList(intrusive_ptr<const GlassDatabase>(this),
@@ -906,7 +906,7 @@
 }
 
 TermList *
-GlassDatabase::open_spelling_termlist(const string & word) const
+GlassDatabase::open_spelling_termlist(const std::string & word) const
 {
     return spelling_table.open_termlist(word);
 }
@@ -921,19 +921,19 @@
 }
 
 Xapian::doccount
-GlassDatabase::get_spelling_frequency(const string & word) const
+GlassDatabase::get_spelling_frequency(const std::string & word) const
 {
     return spelling_table.get_word_frequency(word);
 }
 
 TermList *
-GlassDatabase::open_synonym_termlist(const string & term) const
+GlassDatabase::open_synonym_termlist(const std::string & term) const
 {
     return synonym_table.open_termlist(term);
 }
 
 TermList *
-GlassDatabase::open_synonym_keylist(const string & prefix) const
+GlassDatabase::open_synonym_keylist(const std::string & prefix) const
 {
     GlassCursor * cursor = synonym_table.cursor_get();
     if (!cursor) return NULL;
@@ -942,12 +942,12 @@
 }
 
 string
-GlassDatabase::get_metadata(const string & key) const
+GlassDatabase::get_metadata(const std::string & key) const
 {
     LOGCALL(DB, string, "GlassDatabase::get_metadata", key);
-    string btree_key("\x00\xc0", 2);
+    std::string btree_key("\x00\xc0", 2);
     btree_key += key;
-    string tag;
+    std::string tag;
     (void)postlist_table.get_exact_entry(btree_key, tag);
     RETURN(tag);
 }
@@ -966,7 +966,7 @@
 GlassDatabase::get_revision_info() const
 {
     LOGCALL(DB, string, "GlassDatabase::get_revision_info", NO_ARGS);
-    string buf;
+    std::string buf;
     pack_uint(buf, get_revision_number());
     RETURN(buf);
 }
@@ -1015,7 +1015,7 @@
 
 ///////////////////////////////////////////////////////////////////////////
 
-GlassWritableDatabase::GlassWritableDatabase(const string &dir, int flags,
+GlassWritableDatabase::GlassWritableDatabase(const std::string &dir, int flags,
 					     int block_size)
 	: GlassDatabase(dir, flags, block_size),
 	  change_count(0),
@@ -1128,7 +1128,7 @@
 		new_doclen += wdf;
 		version_file.check_wdf(wdf);
 
-		string tname = *term;
+		std::string tname = *term;
 		if (tname.size() > MAX_SAFE_TERM_LENGTH)
 		    throw Xapian::InvalidArgumentError("Term too long (> " STRINGIZE(MAX_SAFE_TERM_LENGTH) "): " + tname);
 
@@ -1197,7 +1197,7 @@
 
 	termlist.next();
 	while (!termlist.at_end()) {
-	    string tname = termlist.get_termname();
+	    std::string tname = termlist.get_termname();
 	    inverter.delete_positionlist(did, tname);
 
 	    inverter.remove_posting(did, tname, termlist.get_wdf());
@@ -1289,7 +1289,7 @@
 	    version_file.delete_document(old_doclen);
 	    Xapian::termcount new_doclen = old_doclen;
 
-	    string old_tname, new_tname;
+	    std::string old_tname, new_tname;
 
 	    termlist.next();
 	    while (!termlist.at_end() || term != document.termlist_end()) {
@@ -1424,7 +1424,7 @@
 }
 
 void
-GlassWritableDatabase::get_freqs(const string & term,
+GlassWritableDatabase::get_freqs(const std::string & term,
 				 Xapian::doccount * termfreq_ptr,
 				 Xapian::termcount * collfreq_ptr) const
 {
@@ -1444,7 +1444,7 @@
 GlassWritableDatabase::get_value_freq(Xapian::valueno slot) const
 {
     LOGCALL(DB, Xapian::doccount, "GlassWritableDatabase::get_value_freq", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.freq);
     RETURN(GlassDatabase::get_value_freq(slot));
@@ -1454,7 +1454,7 @@
 GlassWritableDatabase::get_value_lower_bound(Xapian::valueno slot) const
 {
     LOGCALL(DB, std::string, "GlassWritableDatabase::get_value_lower_bound", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.lower_bound);
     RETURN(GlassDatabase::get_value_lower_bound(slot));
@@ -1464,14 +1464,14 @@
 GlassWritableDatabase::get_value_upper_bound(Xapian::valueno slot) const
 {
     LOGCALL(DB, std::string, "GlassWritableDatabase::get_value_upper_bound", slot);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     i = value_stats.find(slot);
     if (i != value_stats.end()) RETURN(i->second.upper_bound);
     RETURN(GlassDatabase::get_value_upper_bound(slot));
 }
 
 bool
-GlassWritableDatabase::term_exists(const string & tname) const
+GlassWritableDatabase::term_exists(const std::string & tname) const
 {
     LOGCALL(DB, bool, "GlassWritableDatabase::term_exists", tname);
     Xapian::doccount tf;
@@ -1523,7 +1523,7 @@
 					  const string& term) const
 {
     Assert(did != 0);
-    string data;
+    std::string data;
     if (inverter.get_positionlist(did, term, data)) {
 	pos_list->read_data(data);
 	return;
@@ -1536,7 +1536,7 @@
 					  const string& term) const
 {
     Assert(did != 0);
-    string data;
+    std::string data;
     if (inverter.get_positionlist(did, term, data)) {
 	if (data.empty())
 	    return 0;
@@ -1546,13 +1546,13 @@
 }
 
 PositionList *
-GlassWritableDatabase::open_position_list(Xapian::docid did, const string & term) const
+GlassWritableDatabase::open_position_list(Xapian::docid did, const std::string & term) const
 {
     Assert(did != 0);
 
     AutoPtr<GlassPositionList> poslist(new GlassPositionList);
 
-    string data;
+    std::string data;
     if (inverter.get_positionlist(did, term, data)) {
 	poslist->read_data(data);
     } else if (!poslist->read_data(&position_table, did, term)) {
@@ -1565,7 +1565,7 @@
 }
 
 TermList *
-GlassWritableDatabase::open_allterms(const string & prefix) const
+GlassWritableDatabase::open_allterms(const std::string & prefix) const
 {
     LOGCALL(DB, TermList *, "GlassWritableDatabase::open_allterms", NO_ARGS);
     if (change_count) {
@@ -1594,14 +1594,14 @@
 }
 
 void
-GlassWritableDatabase::add_spelling(const string & word,
+GlassWritableDatabase::add_spelling(const std::string & word,
 				    Xapian::termcount freqinc) const
 {
     spelling_table.add_word(word, freqinc);
 }
 
 void
-GlassWritableDatabase::remove_spelling(const string & word,
+GlassWritableDatabase::remove_spelling(const std::string & word,
 				       Xapian::termcount freqdec) const
 {
     spelling_table.remove_word(word, freqdec);
@@ -1615,37 +1615,37 @@
 }
 
 TermList *
-GlassWritableDatabase::open_synonym_keylist(const string & prefix) const
+GlassWritableDatabase::open_synonym_keylist(const std::string & prefix) const
 {
     synonym_table.merge_changes();
     return GlassDatabase::open_synonym_keylist(prefix);
 }
 
 void
-GlassWritableDatabase::add_synonym(const string & term,
-				   const string & synonym) const
+GlassWritableDatabase::add_synonym(const std::string & term,
+				   const std::string & synonym) const
 {
     synonym_table.add_synonym(term, synonym);
 }
 
 void
-GlassWritableDatabase::remove_synonym(const string & term,
-				      const string & synonym) const
+GlassWritableDatabase::remove_synonym(const std::string & term,
+				      const std::string & synonym) const
 {
     synonym_table.remove_synonym(term, synonym);
 }
 
 void
-GlassWritableDatabase::clear_synonyms(const string & term) const
+GlassWritableDatabase::clear_synonyms(const std::string & term) const
 {
     synonym_table.clear_synonyms(term);
 }
 
 void
-GlassWritableDatabase::set_metadata(const string & key, const string & value)
+GlassWritableDatabase::set_metadata(const std::string & key, const std::string & value)
 {
     LOGCALL_VOID(DB, "GlassWritableDatabase::set_metadata", key | value);
-    string btree_key("\x00\xc0", 2);
+    std::string btree_key("\x00\xc0", 2);
     btree_key += key;
     if (value.empty()) {
 	postlist_table.del(btree_key);
diff -ur xapian-core-1.4.21/backends/glass/glass_database.h xapian-core-1.4.21/backends/glass/glass_database.h
--- xapian-core-1.4.21/backends/glass/glass_database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_database.h	2022-11-08 16:44:00.920513260 +0100
@@ -175,7 +175,7 @@
 
     /** Called if a modifications fail.
      *
-     *  @param msg is a string description of the exception that was
+     *  @param msg is a std::string description of the exception that was
      *  raised when the modifications failed.
      */
     void modifications_failed(glass_revision_number_t new_revision,
@@ -201,7 +201,7 @@
 
     /** Get the revision stored in a changeset.
      */
-    void get_changeset_revisions(const string & path,
+    void get_changeset_revisions(const std::string & path,
 				 glass_revision_number_t * startrev,
 				 glass_revision_number_t * endrev) const;
 
@@ -252,7 +252,7 @@
     Xapian::totallength get_total_length() const;
     Xapian::termcount get_doclength(Xapian::docid did) const;
     Xapian::termcount get_unique_terms(Xapian::docid did) const;
-    void get_freqs(const string & term,
+    void get_freqs(const std::string & term,
 		   Xapian::doccount * termfreq_ptr,
 		   Xapian::termcount * collfreq_ptr) const;
     Xapian::doccount get_value_freq(Xapian::valueno slot) const;
@@ -260,11 +260,11 @@
     std::string get_value_upper_bound(Xapian::valueno slot) const;
     Xapian::termcount get_doclength_lower_bound() const;
     Xapian::termcount get_doclength_upper_bound() const;
-    Xapian::termcount get_wdf_upper_bound(const string & term) const;
-    bool term_exists(const string & tname) const;
+    Xapian::termcount get_wdf_upper_bound(const std::string & term) const;
+    bool term_exists(const std::string & tname) const;
     bool has_positions() const;
 
-    LeafPostList * open_post_list(const string & tname) const;
+    LeafPostList * open_post_list(const std::string & tname) const;
     ValueList * open_value_list(Xapian::valueno slot) const;
     Xapian::Document::Internal* open_document(Xapian::docid did,
 					      bool lazy) const;
@@ -277,23 +277,23 @@
     PositionList* open_position_list(Xapian::docid did,
 				     const string& term) const;
     TermList * open_term_list(Xapian::docid did) const;
-    TermList * open_allterms(const string & prefix) const;
+    TermList * open_allterms(const std::string & prefix) const;
 
-    TermList * open_spelling_termlist(const string & word) const;
+    TermList * open_spelling_termlist(const std::string & word) const;
     TermList * open_spelling_wordlist() const;
-    Xapian::doccount get_spelling_frequency(const string & word) const;
+    Xapian::doccount get_spelling_frequency(const std::string & word) const;
 
-    TermList * open_synonym_termlist(const string & term) const;
-    TermList * open_synonym_keylist(const string & prefix) const;
+    TermList * open_synonym_termlist(const std::string & term) const;
+    TermList * open_synonym_keylist(const std::string & prefix) const;
 
-    string get_metadata(const string & key) const;
+    std::string get_metadata(const std::string & key) const;
     TermList * open_metadata_keylist(const std::string &prefix) const;
     void write_changesets_to_fd(int fd,
-				const string & start_revision,
+				const std::string & start_revision,
 				bool need_whole_db,
 				Xapian::ReplicationInfo * info);
-    string get_revision_info() const;
-    string get_uuid() const;
+    std::string get_revision_info() const;
+    std::string get_uuid() const;
 
     void request_document(Xapian::docid /*did*/) const;
     void readahead_for_query(const Xapian::Query &query);
@@ -332,7 +332,7 @@
 class GlassWritableDatabase : public GlassDatabase {
     mutable Inverter inverter;
 
-    mutable map<Xapian::valueno, ValueStats> value_stats;
+    mutable std::map<Xapian::valueno, ValueStats> value_stats;
 
     /** The number of documents added, deleted, or replaced since the last
      *  flush.
@@ -408,7 +408,7 @@
      *
      *  @param dir directory holding glass tables
      */
-    GlassWritableDatabase(const string &dir, int flags, int block_size);
+    GlassWritableDatabase(const std::string &dir, int flags, int block_size);
 
     ~GlassWritableDatabase();
 
@@ -416,16 +416,16 @@
     //@{
     Xapian::termcount get_doclength(Xapian::docid did) const;
     Xapian::termcount get_unique_terms(Xapian::docid did) const;
-    void get_freqs(const string & term,
+    void get_freqs(const std::string & term,
 		   Xapian::doccount * termfreq_ptr,
 		   Xapian::termcount * collfreq_ptr) const;
     Xapian::doccount get_value_freq(Xapian::valueno slot) const;
     std::string get_value_lower_bound(Xapian::valueno slot) const;
     std::string get_value_upper_bound(Xapian::valueno slot) const;
-    bool term_exists(const string & tname) const;
+    bool term_exists(const std::string & tname) const;
     bool has_positions() const;
 
-    LeafPostList * open_post_list(const string & tname) const;
+    LeafPostList * open_post_list(const std::string & tname) const;
     ValueList * open_value_list(Xapian::valueno slot) const;
 
     void read_position_list(GlassPositionList* pos_list,
@@ -435,19 +435,19 @@
 					 const string& term) const;
     PositionList* open_position_list(Xapian::docid did,
 				     const string& term) const;
-    TermList * open_allterms(const string & prefix) const;
+    TermList * open_allterms(const std::string & prefix) const;
 
-    void add_spelling(const string & word, Xapian::termcount freqinc) const;
-    void remove_spelling(const string & word,
+    void add_spelling(const std::string & word, Xapian::termcount freqinc) const;
+    void remove_spelling(const std::string & word,
 			 Xapian::termcount freqdec) const;
     TermList * open_spelling_wordlist() const;
 
-    TermList * open_synonym_keylist(const string & prefix) const;
-    void add_synonym(const string & word, const string & synonym) const;
-    void remove_synonym(const string & word, const string & synonym) const;
-    void clear_synonyms(const string & word) const;
+    TermList * open_synonym_keylist(const std::string & prefix) const;
+    void add_synonym(const std::string & word, const std::string & synonym) const;
+    void remove_synonym(const std::string & word, const std::string & synonym) const;
+    void clear_synonyms(const std::string & word) const;
 
-    void set_metadata(const string & key, const string & value);
+    void set_metadata(const std::string & key, const std::string & value);
     void invalidate_doc_object(Xapian::Document::Internal * obj) const;
     //@}
 
diff -ur xapian-core-1.4.21/backends/glass/glass_databasereplicator.cc xapian-core-1.4.21/backends/glass/glass_databasereplicator.cc
--- xapian-core-1.4.21/backends/glass/glass_databasereplicator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_databasereplicator.cc	2022-11-08 16:44:15.360461927 +0100
@@ -64,7 +64,7 @@
 	"/spelling." GLASS_TABLE_EXTENSION "\0"
 	"/synonym." GLASS_TABLE_EXTENSION;
 
-GlassDatabaseReplicator::GlassDatabaseReplicator(const string & db_dir_)
+GlassDatabaseReplicator::GlassDatabaseReplicator(const std::string & db_dir_)
     : db_dir(db_dir_)
 {
     std::fill_n(fds, sizeof(fds) / sizeof(fds[0]), -1);
@@ -96,8 +96,8 @@
 }
 
 bool
-GlassDatabaseReplicator::check_revision_at_least(const string & rev,
-						 const string & target) const
+GlassDatabaseReplicator::check_revision_at_least(const std::string & rev,
+						 const std::string & target) const
 {
     LOGCALL(DB, bool, "GlassDatabaseReplicator::check_revision_at_least", rev | target);
 
@@ -107,13 +107,13 @@
     const char * ptr = rev.data();
     const char * end = ptr + rev.size();
     if (!unpack_uint(&ptr, end, &rev_val)) {
-	throw NetworkError("Invalid revision string supplied to check_revision_at_least");
+	throw NetworkError("Invalid revision std::string supplied to check_revision_at_least");
     }
 
     ptr = target.data();
     end = ptr + target.size();
     if (!unpack_uint(&ptr, end, &target_val)) {
-	throw NetworkError("Invalid revision string supplied to check_revision_at_least");
+	throw NetworkError("Invalid revision std::string supplied to check_revision_at_least");
     }
 
     RETURN(rev_val >= target_val);
@@ -145,11 +145,11 @@
     }
 
     // Write size bytes from start of buf to new version file.
-    string tmpfile = db_dir;
+    std::string tmpfile = db_dir;
     tmpfile += "/v.rtmp";
     int fd = posixy_open(tmpfile.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0666);
     if (fd == -1) {
-	string msg = "Failed to open ";
+	std::string msg = "Failed to open ";
 	msg += tmpfile;
 	throw DatabaseError(msg, errno);
     }
@@ -158,10 +158,10 @@
 	io_write(fd, buf.data(), size);
 	io_sync(fd);
     }
-    string version_file = db_dir;
+    std::string version_file = db_dir;
     version_file += "/iamglass";
     if (!io_tmp_rename(tmpfile, version_file)) {
-	string msg("Couldn't create new version file ");
+	std::string msg("Couldn't create new version file ");
 	msg += version_file;
 	throw DatabaseError(msg, errno);
     }
@@ -172,7 +172,7 @@
 void
 GlassDatabaseReplicator::process_changeset_chunk_blocks(Glass::table_type table,
 							unsigned v,
-							string & buf,
+							std::string & buf,
 							RemoteConnection & conn,
 							double end_time) const
 {
@@ -192,11 +192,11 @@
 
     int fd = fds[table];
     if (fd == -1) {
-	string db_path = db_dir;
+	std::string db_path = db_dir;
 	db_path += dbnames + table * (11 + CONST_STRLEN(GLASS_TABLE_EXTENSION));
 	fd = posixy_open(db_path.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0666);
 	if (fd == -1) {
-	    string msg = "Failed to open ";
+	    std::string msg = "Failed to open ";
 	    msg += db_path;
 	    throw DatabaseError(msg, errno);
 	}
@@ -223,7 +223,7 @@
 
     // Lock the database to perform modifications.
     FlintLock lock(db_dir);
-    string explanation;
+    std::string explanation;
     FlintLock::reason why = lock.lock(true, false, explanation);
     if (why != FlintLock::SUCCESS) {
 	lock.throw_databaselockerror(why, db_dir, explanation);
@@ -234,7 +234,7 @@
 	throw_connection_closed_unexpectedly();
     AssertEq(type, REPL_REPLY_CHANGESET);
 
-    string buf;
+    std::string buf;
     // Read enough to be certain that we've got the header part of the
     // changeset.
 
diff -ur xapian-core-1.4.21/backends/glass/glass_dbcheck.cc xapian-core-1.4.21/backends/glass/glass_dbcheck.cc
--- xapian-core-1.4.21/backends/glass/glass_dbcheck.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_dbcheck.cc	2022-11-08 16:44:15.352461955 +0100
@@ -46,7 +46,7 @@
 using namespace std;
 
 static inline bool
-is_user_metadata_key(const string & key)
+is_user_metadata_key(const std::string & key)
 {
     return key.size() > 1 && key[0] == '\0' && key[1] == '\xc0';
 }
@@ -58,10 +58,10 @@
 };
 
 size_t
-check_glass_table(const char * tablename, const string &db_dir, int fd,
+check_glass_table(const char * tablename, const std::string &db_dir, int fd,
 		  off_t offset_,
 		  const GlassVersion & version_file, int opts,
-		  vector<Xapian::termcount> & doclens, ostream * out)
+		  std::vector<Xapian::termcount> & doclens, ostream * out)
 {
     Xapian::docid db_last_docid = version_file.get_last_docid();
     if (out)
@@ -69,7 +69,7 @@
     if (fd < 0) {
 	if (strcmp(tablename, "postlist") != 0) {
 	    // Other filenames are created lazily, so may not exist.
-	    string filename(db_dir);
+	    std::string filename(db_dir);
 	    filename += '/';
 	    filename += tablename;
 	    filename += "." GLASS_TABLE_EXTENSION;
@@ -102,15 +102,15 @@
 
     if (strcmp(tablename, "postlist") == 0) {
 	// Now check the structure of each postlist in the table.
-	map<Xapian::valueno, VStats> valuestats;
-	string current_term;
+	std::map<Xapian::valueno, VStats> valuestats;
+	std::string current_term;
 	Xapian::docid lastdid = 0;
 	Xapian::termcount termfreq = 0, collfreq = 0;
 	Xapian::termcount tf = 0, cf = 0;
 	Xapian::doccount num_doclens = 0;
 
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    if (is_user_metadata_key(key)) {
 		// User metadata can be anything, so we can't do any particular
@@ -340,7 +340,7 @@
 		end = p + cursor->current_tag.size();
 
 		while (true) {
-		    string value;
+		    std::string value;
 		    if (!unpack_string(&p, end, value)) {
 			if (out)
 			    *out << "Failed to unpack value from chunk" << endl;
@@ -405,7 +405,7 @@
 	    pos = key.data();
 	    end = pos + key.size();
 
-	    string term;
+	    std::string term;
 	    Xapian::docid did;
 	    if (!unpack_string_preserving_sort(&pos, end, term)) {
 		if (out)
@@ -584,7 +584,7 @@
 	    ++errors;
 	}
 
-	map<Xapian::valueno, VStats>::const_iterator i;
+	std::map<Xapian::valueno, VStats>::const_iterator i;
 	for (i = valuestats.begin(); i != valuestats.end(); ++i) {
 	    if (i->second.freq != i->second.freq_real) {
 		if (out)
@@ -608,7 +608,7 @@
 
 	// Now check the contents of the docdata table.
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
@@ -652,7 +652,7 @@
 	Xapian::doccount num_termlists = 0;
 	Xapian::doccount num_slotsused_entries = 0;
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
@@ -781,7 +781,7 @@
 	    }
 
 	    Xapian::termcount actual_doclen = 0, actual_termlist_size = 0;
-	    string current_tname;
+	    std::string current_tname;
 
 	    bool bad = false;
 	    while (pos != end) {
@@ -867,13 +867,13 @@
     } else if (strcmp(tablename, "position") == 0) {
 	// Now check the contents of the position table.
 	for ( ; !cursor->after_end(); cursor->next()) {
-	    string & key = cursor->current_key;
+	    std::string & key = cursor->current_key;
 
 	    // Get docid from key.
 	    const char * pos = key.data();
 	    const char * end = pos + key.size();
 
-	    string term;
+	    std::string term;
 	    if (!unpack_string_preserving_sort(&pos, end, term)) {
 		if (out)
 		    *out << "Error unpacking term from key" << endl;
@@ -916,7 +916,7 @@
 
 	    cursor->read_tag();
 
-	    const string & data = cursor->current_tag;
+	    const std::string & data = cursor->current_tag;
 	    pos = data.data();
 	    end = pos + data.size();
 
diff -ur xapian-core-1.4.21/backends/glass/glass_docdata.h xapian-core-1.4.21/backends/glass/glass_docdata.h
--- xapian-core-1.4.21/backends/glass/glass_docdata.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_docdata.h	2022-11-08 16:44:00.932513218 +0100
@@ -52,7 +52,7 @@
 
     /** Get the document data for document @a did.
      *
-     *  If the document doesn't exist, the empty string is returned.
+     *  If the document doesn't exist, the empty std::string is returned.
      *
      *  @param did	The docid to set the document data for.
      */
diff -ur xapian-core-1.4.21/backends/glass/glass_document.cc xapian-core-1.4.21/backends/glass/glass_document.cc
--- xapian-core-1.4.21/backends/glass/glass_document.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_document.cc	2022-11-08 16:44:15.368461899 +0100
@@ -44,7 +44,7 @@
 /** Retrieve all value values from the database
  */
 void
-GlassDocument::do_get_all_values(map<Xapian::valueno, string> & values_) const
+GlassDocument::do_get_all_values(std::map<Xapian::valueno, string> & values_) const
 {
     LOGCALL_VOID(DB, "GlassDocument::do_get_all_values", values_);
     value_manager->get_all_values(values_, did);
diff -ur xapian-core-1.4.21/backends/glass/glass_document.h xapian-core-1.4.21/backends/glass/glass_document.h
--- xapian-core-1.4.21/backends/glass/glass_document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_document.h	2022-11-08 16:44:00.928513231 +0100
@@ -53,9 +53,9 @@
 
   public:
     /** Implementation of virtual methods @{ */
-    string do_get_value(Xapian::valueno slot) const;
-    void do_get_all_values(map<Xapian::valueno, string> & values_) const;
-    string do_get_data() const;
+    std::string do_get_value(Xapian::valueno slot) const;
+    void do_get_all_values(std::map<Xapian::valueno, string> & values_) const;
+    std::string do_get_data() const;
     /** @} */
 };
 
diff -ur xapian-core-1.4.21/backends/glass/glass_inverter.cc xapian-core-1.4.21/backends/glass/glass_inverter.cc
--- xapian-core-1.4.21/backends/glass/glass_inverter.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_inverter.cc	2022-11-08 16:44:15.368461899 +0100
@@ -35,11 +35,11 @@
 void
 Inverter::store_positions(const GlassPositionListTable & position_table,
 			  Xapian::docid did,
-			  const string & tname,
-			  const vector<Xapian::termpos> & posvec,
+			  const std::string & tname,
+			  const std::vector<Xapian::termpos> & posvec,
 			  bool modifying)
 {
-    string s;
+    std::string s;
     position_table.pack(s, posvec);
     if (modifying && has_positions_cache != 0) {
 	// If we add positions we must then have positions, but if we remove
@@ -48,7 +48,7 @@
 
 	auto i = pos_changes.find(tname);
 	if (i != pos_changes.end()) {
-	    map<Xapian::docid, string> & m = i->second;
+	    std::map<Xapian::docid, string> & m = i->second;
 	    auto j = m.find(did);
 	    if (j != m.end()) {
 		// Update existing entry.
@@ -56,8 +56,8 @@
 		return;
 	    }
 	}
-	const string & key = position_table.make_key(did, tname);
-	string old_tag;
+	const std::string & key = position_table.make_key(did, tname);
+	std::string old_tag;
 	if (position_table.get_exact_entry(key, old_tag) && s == old_tag) {
 	    // Identical to existing entry on disk.
 	    return;
@@ -72,7 +72,7 @@
 void
 Inverter::set_positionlist(const GlassPositionListTable & position_table,
 			   Xapian::docid did,
-			   const string & tname,
+			   const std::string & tname,
 			   const Xapian::TermIterator & term,
 			   bool modifying)
 {
@@ -86,7 +86,7 @@
     } else {
 	Xapian::PositionIterator pos = term.positionlist_begin();
 	if (pos != term.positionlist_end()) {
-	    vector<Xapian::termpos> posvec(pos, Xapian::PositionIterator());
+	    std::vector<Xapian::termpos> posvec(pos, Xapian::PositionIterator());
 	    store_positions(position_table, did, tname, posvec, modifying);
 	    return;
 	}
@@ -98,30 +98,30 @@
 
 void
 Inverter::set_positionlist(Xapian::docid did,
-			   const string & term,
-			   const string & s)
+			   const std::string & term,
+			   const std::string & s)
 {
     has_positions_cache = s.empty() ? -1 : 1;
-    pos_changes.insert(make_pair(term, map<Xapian::docid, string>()))
+    pos_changes.insert(make_pair(term, std::map<Xapian::docid, string>()))
 	.first->second[did] = s;
 }
 
 void
 Inverter::delete_positionlist(Xapian::docid did,
-			      const string & term)
+			      const std::string & term)
 {
     set_positionlist(did, term, string());
 }
 
 bool
 Inverter::get_positionlist(Xapian::docid did,
-			   const string & term,
-			   string & s) const
+			   const std::string & term,
+			   std::string & s) const
 {
     auto i = pos_changes.find(term);
     if (i == pos_changes.end())
 	return false;
-    const map<Xapian::docid, string> & m = i->second;
+    const std::map<Xapian::docid, string> & m = i->second;
     auto j = m.find(did);
     if (j == m.end())
 	return false;
@@ -137,9 +137,9 @@
 	// efficient?  E.g. how many sets and deletes we had in total perhaps.
 	glass_tablesize_t changes = 0;
 	for (const auto& i : pos_changes) {
-	    const map<Xapian::docid, string>& m = i.second;
+	    const std::map<Xapian::docid, string>& m = i.second;
 	    for (const auto& j : m) {
-		const string & s = j.second;
+		const std::string & s = j.second;
 		if (!s.empty())
 		    return true;
 		++changes;
@@ -160,9 +160,9 @@
 }
 
 void
-Inverter::flush_post_list(GlassPostListTable & table, const string & term)
+Inverter::flush_post_list(GlassPostListTable & table, const std::string & term)
 {
-    map<string, PostingChanges>::iterator i;
+    std::map<string, PostingChanges>::iterator i;
     i = postlist_changes.find(term);
     if (i == postlist_changes.end()) return;
 
@@ -174,7 +174,7 @@
 void
 Inverter::flush_all_post_lists(GlassPostListTable & table)
 {
-    map<string, PostingChanges>::const_iterator i;
+    std::map<string, PostingChanges>::const_iterator i;
     for (i = postlist_changes.begin(); i != postlist_changes.end(); ++i) {
 	table.merge_changes(i->first, i->second);
     }
@@ -182,14 +182,14 @@
 }
 
 void
-Inverter::flush_post_lists(GlassPostListTable & table, const string & pfx)
+Inverter::flush_post_lists(GlassPostListTable & table, const std::string & pfx)
 {
     if (pfx.empty())
 	return flush_all_post_lists(table);
 
-    map<string, PostingChanges>::iterator i, begin, end;
+    std::map<string, PostingChanges>::iterator i, begin, end;
     begin = postlist_changes.lower_bound(pfx);
-    string pfxinc = pfx;
+    std::string pfxinc = pfx;
     while (true) {
 	if (pfxinc.back() != '\xff') {
 	    ++pfxinc.back();
@@ -223,11 +223,11 @@
 Inverter::flush_pos_lists(GlassPositionListTable & table)
 {
     for (auto i : pos_changes) {
-	const string & term = i.first;
-	const map<Xapian::docid, string> & m = i.second;
+	const std::string & term = i.first;
+	const std::map<Xapian::docid, string> & m = i.second;
 	for (auto j : m) {
 	    Xapian::docid did = j.first;
-	    const string & s = j.second;
+	    const std::string & s = j.second;
 	    if (!s.empty())
 		table.set_positionlist(did, term, s);
 	    else
diff -ur xapian-core-1.4.21/backends/glass/glass_metadata.cc xapian-core-1.4.21/backends/glass/glass_metadata.cc
--- xapian-core-1.4.21/backends/glass/glass_metadata.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_metadata.cc	2022-11-08 16:44:15.364461914 +0100
@@ -38,7 +38,7 @@
 GlassMetadataTermList::GlassMetadataTermList(
 	intrusive_ptr<const Xapian::Database::Internal> database_,
 	GlassCursor * cursor_,
-	const string &prefix_)
+	const std::string &prefix_)
 	: database(database_), cursor(cursor_), prefix(string("\x00\xc0", 2) + prefix_)
 {
     LOGCALL_CTOR(DB, "GlassMetadataTermList", database_ | cursor_ | prefix_);
@@ -85,7 +85,7 @@
 }
 
 TermList *
-GlassMetadataTermList::skip_to(const string &key)
+GlassMetadataTermList::skip_to(const std::string &key)
 {
     LOGCALL(DB, TermList *, "GlassMetadataTermList::skip_to", key);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/glass/glass_positionlist.cc xapian-core-1.4.21/backends/glass/glass_positionlist.cc
--- xapian-core-1.4.21/backends/glass/glass_positionlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_positionlist.cc	2022-11-08 16:44:15.380461857 +0100
@@ -36,7 +36,7 @@
 
 void
 GlassPositionListTable::pack(string & s,
-			     const vector<Xapian::termpos> & vec) const
+			     const std::vector<Xapian::termpos> & vec) const
 {
     LOGCALL_VOID(DB, "GlassPositionListTable::pack", s | vec);
     Assert(!vec.empty());
@@ -79,11 +79,11 @@
 
 Xapian::termcount
 GlassPositionListTable::positionlist_count(Xapian::docid did,
-					   const string & term) const
+					   const std::string & term) const
 {
     LOGCALL(DB, Xapian::termcount, "GlassPositionListTable::positionlist_count", did | term);
 
-    string data;
+    std::string data;
     if (!get_exact_entry(make_key(did, term), data)) {
 	RETURN(0);
     }
@@ -94,7 +94,7 @@
 ///////////////////////////////////////////////////////////////////////////
 
 bool
-GlassPositionList::read_data(const string & data)
+GlassPositionList::read_data(const std::string & data)
 {
     LOGCALL(DB, bool, "GlassPositionList::read_data", data);
 
@@ -133,7 +133,7 @@
 
 bool
 GlassPositionList::read_data(const GlassTable * table, Xapian::docid did,
-			     const string & tname)
+			     const std::string & tname)
 {
     LOGCALL(DB, bool, "GlassPositionList::read_data", table | did | tname);
     if (!cursor.get()) {
diff -ur xapian-core-1.4.21/backends/glass/glass_positionlist.h xapian-core-1.4.21/backends/glass/glass_positionlist.h
--- xapian-core-1.4.21/backends/glass/glass_positionlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_positionlist.h	2022-11-08 16:44:00.928513231 +0100
@@ -32,12 +32,12 @@
 
 #include <string>
 
-using namespace std;
+using std::string;
 
 class GlassPositionListTable : public GlassLazyTable {
   public:
-    static string make_key(Xapian::docid did, const string & term) {
-	string key;
+    static std::string make_key(Xapian::docid did, const std::string & term) {
+	std::string key;
 	pack_string_preserving_sort(key, term);
 	pack_uint_preserving_sort(key, did);
 	return key;
@@ -51,7 +51,7 @@
      *  @param dbdir		The directory the glass database is stored in.
      *  @param readonly		true if we're opening read-only, else false.
      */
-    GlassPositionListTable(const string & dbdir, bool readonly)
+    GlassPositionListTable(const std::string & dbdir, bool readonly)
 	: GlassLazyTable("position", dbdir + "/position.", readonly) { }
 
     GlassPositionListTable(int fd, off_t offset_, bool readonly_)
@@ -59,19 +59,19 @@
 
     /** Pack a position list into a string.
      *
-     *  @param s The string to append the position list data to.
+     *  @param s The std::string to append the position list data to.
      */
     void pack(string & s, const std::vector<Xapian::termpos> & vec) const;
 
     /** Set the position list for term tname in document did.
      */
-    void set_positionlist(Xapian::docid did, const string & tname,
-			  const string & s) {
+    void set_positionlist(Xapian::docid did, const std::string & tname,
+			  const std::string & s) {
 	add(make_key(did, tname), s);
     }
 
     /// Delete the position list for term tname in document did.
-    void delete_positionlist(Xapian::docid did, const string & tname) {
+    void delete_positionlist(Xapian::docid did, const std::string & tname) {
 	del(make_key(did, tname));
     }
 
@@ -80,7 +80,7 @@
 
     /// Return the number of entries in specified position list.
     Xapian::termcount positionlist_count(Xapian::docid did,
-					 const string & term) const;
+					 const std::string & term) const;
 };
 
 /** A position list in a glass database. */
@@ -121,7 +121,7 @@
 
     /// Construct and initialise with data.
     GlassPositionList(const GlassTable * table, Xapian::docid did,
-		      const string & tname) {
+		      const std::string & tname) {
 	(void)read_data(table, did, tname);
     }
 
@@ -129,14 +129,14 @@
      *
      *  @return true if position data was read.
      */
-    bool read_data(const string & data);
+    bool read_data(const std::string & data);
 
     /** Fill list with data, and move the position to the start.
      *
      *  @return true if position data was read.
      */
     bool read_data(const GlassTable * table, Xapian::docid did,
-		   const string & tname);
+		   const std::string & tname);
 
     /// Returns size of position list.
     Xapian::termcount get_approx_size() const;
diff -ur xapian-core-1.4.21/backends/glass/glass_postlist.cc xapian-core-1.4.21/backends/glass/glass_postlist.cc
--- xapian-core-1.4.21/backends/glass/glass_postlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_postlist.cc	2022-11-08 16:44:15.348461970 +0100
@@ -53,15 +53,15 @@
 }
 
 static inline bool
-get_tname_from_key(const char **src, const char *end, string &tname)
+get_tname_from_key(const char **src, const char *end, std::string &tname)
 {
     return unpack_string_preserving_sort(src, end, tname);
 }
 
 static inline bool
-check_tname_in_key_lite(const char **keypos, const char *keyend, const string &tname)
+check_tname_in_key_lite(const char **keypos, const char *keyend, const std::string &tname)
 {
-    string tname_in_key;
+    std::string tname_in_key;
 
     if (keyend - *keypos >= 2 && (*keypos)[0] == '\0' && (*keypos)[1] == '\xe0') {
 	*keypos += 2;
@@ -76,7 +76,7 @@
 }
 
 static inline bool
-check_tname_in_key(const char **keypos, const char *keyend, const string &tname)
+check_tname_in_key(const char **keypos, const char *keyend, const std::string &tname)
 {
     if (*keypos == keyend) return false;
 
@@ -150,13 +150,13 @@
 }
 
 void
-GlassPostListTable::get_freqs(const string & term,
+GlassPostListTable::get_freqs(const std::string & term,
 			      Xapian::doccount * termfreq_ptr,
 			      Xapian::termcount * collfreq_ptr,
 			      Xapian::termcount * wdfub_ptr) const
 {
-    string key = make_key(term);
-    string tag;
+    std::string key = make_key(term);
+    std::string tag;
     if (!get_exact_entry(key, tag)) {
 	if (termfreq_ptr)
 	    *termfreq_ptr = 0;
@@ -187,7 +187,7 @@
 		Xapian::termcount first_wdf;
 		if (!unpack_uint(&p, e, &first_wdf))
 		    report_read_error(p);
-		*wdfub_ptr = max(cf - first_wdf, first_wdf);
+		*wdfub_ptr = std::max(cf - first_wdf, first_wdf);
 	    }
 	}
     }
@@ -233,9 +233,9 @@
  */
 class Glass::PostlistChunkWriter {
   public:
-    PostlistChunkWriter(const string &orig_key_,
+    PostlistChunkWriter(const std::string &orig_key_,
 			bool is_first_chunk_,
-			const string &tname_,
+			const std::string &tname_,
 			bool is_last_chunk_);
 
     /// Append an entry to this chunk.
@@ -244,7 +244,7 @@
 
     /// Append a block of raw entries to this chunk.
     void raw_append(Xapian::docid first_did_, Xapian::docid current_did_,
-		    const string & s) {
+		    const std::string & s) {
 	Assert(!started);
 	first_did = first_did_;
 	current_did = current_did_;
@@ -261,8 +261,8 @@
     void flush(GlassTable *table);
 
   private:
-    string orig_key;
-    string tname;
+    std::string orig_key;
+    std::string tname;
     bool is_first_chunk;
     bool is_last_chunk;
     bool started;
@@ -270,7 +270,7 @@
     Xapian::docid first_did;
     Xapian::docid current_did;
 
-    string chunk;
+    std::string chunk;
 };
 
 using Glass::PostlistChunkWriter;
@@ -280,7 +280,7 @@
  *  entries in a postlist.
  */
 class Glass::PostlistChunkReader {
-    string data;
+    std::string data;
 
     const char *pos;
     const char *end;
@@ -294,9 +294,9 @@
     /** Initialise the postlist chunk reader.
      *
      *  @param first_did  First document id in this chunk.
-     *  @param data       The tag string with the header removed.
+     *  @param data       The tag std::string with the header removed.
      */
-    PostlistChunkReader(Xapian::docid first_did, const string & data_)
+    PostlistChunkReader(Xapian::docid first_did, const std::string & data_)
 	: data(data_), pos(data.data()), end(pos + data.length()), at_end(data.empty()), did(first_did)
     {
 	if (!at_end) read_wdf(&pos, end, &wdf);
@@ -331,9 +331,9 @@
     }
 }
 
-PostlistChunkWriter::PostlistChunkWriter(const string &orig_key_,
+PostlistChunkWriter::PostlistChunkWriter(const std::string &orig_key_,
 					 bool is_first_chunk_,
-					 const string &tname_,
+					 const std::string &tname_,
 					 bool is_last_chunk_)
 	: orig_key(orig_key_),
 	  tname(tname_), is_first_chunk(is_first_chunk_),
@@ -377,7 +377,7 @@
 			  Xapian::termcount collectionfreq,
 			  Xapian::docid new_did)
 {
-    string chunk;
+    std::string chunk;
     pack_uint(chunk, entries);
     pack_uint(chunk, collectionfreq);
     pack_uint(chunk, new_did - 1);
@@ -392,7 +392,7 @@
 		    Xapian::docid new_final_did)
 {
     Assert(new_final_did >= new_first_did);
-    string chunk;
+    std::string chunk;
     pack_bool(chunk, new_is_last_chunk);
     pack_uint(chunk, new_final_did - new_first_did);
     return chunk;
@@ -506,13 +506,13 @@
 		read_start_of_chunk(&tagpos, tagend, new_first_did,
 				    &new_is_last_chunk);
 
-	    string chunk_data(tagpos, tagend);
+	    std::string chunk_data(tagpos, tagend);
 
 	    // First remove the renamed tag
 	    table->del(cursor->current_key);
 
 	    // And now write it as the first chunk
-	    string tag;
+	    std::string tag;
 	    tag = make_start_of_first_chunk(num_ent, coll_freq, new_first_did);
 	    tag += make_start_of_chunk(new_is_last_chunk,
 					      new_first_did,
@@ -549,7 +549,7 @@
 
 	    // Now update the last_chunk
 	    cursor->read_tag();
-	    string tag = cursor->current_tag;
+	    std::string tag = cursor->current_tag;
 
 	    const char *tagpos = tag.data();
 	    const char *tagend = tagpos + tag.size();
@@ -587,7 +587,7 @@
 	 *
 	 * The subcases just affect the chunk header.
 	 */
-	string tag;
+	std::string tag;
 
 	/* First write the header, which depends on whether this is the
 	 * first chunk.
@@ -597,7 +597,7 @@
 	     * and we just have to write this one back to disk.
 	     */
 	    LOGLINE(DB, "PostlistChunkWriter::flush(): rewriting the first chunk, which still has items in it");
-	    string key = GlassPostListTable::make_key(tname);
+	    std::string key = GlassPostListTable::make_key(tname);
 	    bool ok = table->get_exact_entry(key, tag);
 	    (void)ok;
 	    Assert(ok);
@@ -641,7 +641,7 @@
 	if (!unpack_uint_preserving_sort(&keypos, keyend, &initial_did)) {
 	    report_read_error(keypos);
 	}
-	string new_key;
+	std::string new_key;
 	if (initial_did != first_did) {
 	    /* The fiddlier case:
 	     * Create a new tag with the correct key, and replace
@@ -696,7 +696,7 @@
  *  standard chunk.
  */
 GlassPostList::GlassPostList(intrusive_ptr<const GlassDatabase> this_db_,
-			     const string & term_,
+			     const std::string & term_,
 			     bool keep_reference)
 	: LeafPostList(term_),
 	  this_db(keep_reference ? this_db_ : NULL),
@@ -709,7 +709,7 @@
 }
 
 GlassPostList::GlassPostList(intrusive_ptr<const GlassDatabase> this_db_,
-			     const string & term_,
+			     const std::string & term_,
 			     GlassCursor * cursor_)
 	: LeafPostList(term_),
 	  this_db(this_db_),
@@ -724,7 +724,7 @@
 void
 GlassPostList::init()
 {
-    string key = GlassPostListTable::make_key(term);
+    std::string key = GlassPostListTable::make_key(term);
     int found = cursor->find_entry(key);
     if (!found) {
 	LOGLINE(DB, "postlist for term not found");
@@ -749,7 +749,7 @@
     read_wdf(&pos, end, &wdf);
     // This works even if there's only one entry (when wdf == collfreq)
     // or when collfreq is 0 (=> wdf is 0 too).
-    wdf_upper_bound = max(collfreq - wdf, wdf);
+    wdf_upper_bound = std::max(collfreq - wdf, wdf);
     LOGLINE(DB, "Initial docid " << did);
 }
 
@@ -1040,7 +1040,7 @@
 string
 GlassPostList::get_description() const
 {
-    string desc;
+    std::string desc;
     description_append(desc, term);
     desc += ":";
     desc += str(number_of_entries);
@@ -1049,14 +1049,14 @@
 
 // Returns the last did to allow in this chunk.
 Xapian::docid
-GlassPostListTable::get_chunk(const string &tname,
+GlassPostListTable::get_chunk(const std::string &tname,
 			      Xapian::docid did, bool adding,
 			      PostlistChunkReader ** from,
 			      PostlistChunkWriter **to)
 {
     LOGCALL(DB, Xapian::docid, "GlassPostListTable::get_chunk", tname | did | adding | from | to);
     // Get chunk containing entry
-    string key = make_key(tname, did);
+    std::string key = make_key(tname, did);
 
     // Find the right chunk
     AutoPtr<GlassCursor> cursor(cursor_get());
@@ -1134,7 +1134,7 @@
 }
 
 void
-GlassPostListTable::merge_doclen_changes(const map<Xapian::docid, Xapian::termcount> & doclens)
+GlassPostListTable::merge_doclen_changes(const std::map<Xapian::docid, Xapian::termcount> & doclens)
 {
     LOGCALL_VOID(DB, "GlassPostListTable::merge_doclen_changes", doclens);
 
@@ -1145,15 +1145,15 @@
     if (doclens.empty()) return;
 
     // Ensure there's a first chunk.
-    string current_key = make_key(string());
+    std::string current_key = make_key(string());
     if (!key_exists(current_key)) {
 	LOGLINE(DB, "Adding dummy first chunk");
-	string newtag = make_start_of_first_chunk(0, 0, 0);
+	std::string newtag = make_start_of_first_chunk(0, 0, 0);
 	newtag += make_start_of_chunk(true, 0, 0);
 	add(current_key, newtag);
     }
 
-    map<Xapian::docid, Xapian::termcount>::const_iterator j;
+    std::map<Xapian::docid, Xapian::termcount>::const_iterator j;
     j = doclens.begin();
     Assert(j != doclens.end()); // This case is caught above.
 
@@ -1202,14 +1202,14 @@
 }
 
 void
-GlassPostListTable::merge_changes(const string &term,
+GlassPostListTable::merge_changes(const std::string &term,
 				  const Inverter::PostingChanges & changes)
 {
     {
 	// Rewrite the first chunk of this posting list with the updated
 	// termfreq and collfreq.
-	string current_key = make_key(term);
-	string tag;
+	std::string current_key = make_key(term);
+	std::string tag;
 	(void)get_exact_entry(current_key, tag);
 
 	// Read start of first chunk to get termfreq and collfreq.
@@ -1255,7 +1255,7 @@
 	collfreq += changes.get_cfdelta();
 
 	// Rewrite start of first chunk to update termfreq and collfreq.
-	string newhdr = make_start_of_first_chunk(termfreq, collfreq, firstdid);
+	std::string newhdr = make_start_of_first_chunk(termfreq, collfreq, firstdid);
 	newhdr += make_start_of_chunk(islast, firstdid, lastdid);
 	if (pos == end) {
 	    add(current_key, newhdr);
@@ -1265,7 +1265,7 @@
 	    add(current_key, tag);
 	}
     }
-    map<Xapian::docid, Xapian::termcount>::const_iterator j;
+    std::map<Xapian::docid, Xapian::termcount>::const_iterator j;
     j = changes.pl_changes.begin();
     Assert(j != changes.pl_changes.end()); // This case is caught above.
 
diff -ur xapian-core-1.4.21/backends/glass/glass_postlist.h xapian-core-1.4.21/backends/glass/glass_postlist.h
--- xapian-core-1.4.21/backends/glass/glass_postlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_postlist.h	2022-11-08 16:44:00.924513246 +0100
@@ -37,7 +37,9 @@
 #include <map>
 #include <string>
 
-using namespace std;
+using std::string;
+using std::map;
+using std::pair;
 
 class GlassCursor;
 class GlassDatabase;
@@ -69,7 +71,7 @@
      *  @param readonly_      - whether to open the table for read only
      *                          access.
      */
-    GlassPostListTable(const string & path_, bool readonly_)
+    GlassPostListTable(const std::string & path_, bool readonly_)
 	: GlassTable("postlist", path_ + "/postlist.", readonly_),
 	  doclen_pl()
     { }
@@ -90,7 +92,7 @@
 		       const Inverter::PostingChanges& changes);
 
     /// Merge document length changes.
-    void merge_doclen_changes(const map<Xapian::docid,
+    void merge_doclen_changes(const std::map<Xapian::docid,
 					Xapian::termcount>& doclens);
 
     Xapian::docid get_chunk(const string& tname,
@@ -99,16 +101,16 @@
 			    Glass::PostlistChunkWriter** to);
 
     /// Compose a key from a termname and docid.
-    static string make_key(const string& term, Xapian::docid did) {
+    static std::string make_key(const string& term, Xapian::docid did) {
 	return pack_glass_postlist_key(term, did);
     }
 
     /// Compose a key from a termname.
-    static string make_key(const string & term) {
+    static std::string make_key(const std::string & term) {
 	return pack_glass_postlist_key(term);
     }
 
-    bool term_exists(const string & term) const {
+    bool term_exists(const std::string & term) const {
 	return key_exists(make_key(term));
     }
 
@@ -240,7 +242,7 @@
     bool move_forward_in_chunk_to_at_least(Xapian::docid desired_did);
 
     GlassPostList(Xapian::Internal::intrusive_ptr<const GlassDatabase> this_db_,
-		  const string & term,
+		  const std::string & term,
 		  GlassCursor * cursor_);
 
     void init();
@@ -248,7 +250,7 @@
   public:
     /// Default constructor.
     GlassPostList(Xapian::Internal::intrusive_ptr<const GlassDatabase> this_db_,
-		  const string & term,
+		  const std::string & term,
 		  bool keep_reference);
 
     /// Destructor.
diff -ur xapian-core-1.4.21/backends/glass/glass_replicate_internal.h xapian-core-1.4.21/backends/glass/glass_replicate_internal.h
--- xapian-core-1.4.21/backends/glass/glass_replicate_internal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_replicate_internal.h	2022-11-08 16:44:00.928513231 +0100
@@ -23,7 +23,7 @@
 #ifndef XAPIAN_INCLUDED_GLASS_REPLICATE_INTERNAL_H
 #define XAPIAN_INCLUDED_GLASS_REPLICATE_INTERNAL_H
 
-// Magic string used to recognise a changeset file.
+// Magic std::string used to recognise a changeset file.
 #define CHANGES_MAGIC_STRING "GlassChanges"
 
 // The current version of changeset files.
diff -ur xapian-core-1.4.21/backends/glass/glass_spelling.cc xapian-core-1.4.21/backends/glass/glass_spelling.cc
--- xapian-core-1.4.21/backends/glass/glass_spelling.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_spelling.cc	2022-11-08 16:44:15.364461914 +0100
@@ -51,14 +51,14 @@
 	auto d = changes.begin();
 	if (d == changes.end()) continue;
 
-	string updated;
-	string current;
+	std::string updated;
+	std::string current;
 	PrefixCompressedStringWriter out(updated);
 	if (get_exact_entry(key, current)) {
 	    PrefixCompressedStringItor in(current);
 	    updated.reserve(current.size()); // FIXME plus some?
 	    while (!in.at_end() && d != changes.end()) {
-		const string & word = *in;
+		const std::string & word = *in;
 		Assert(d != changes.end());
 		int cmp = word.compare(*d);
 		if (cmp < 0) {
@@ -92,12 +92,12 @@
     }
     termlist_deltas.clear();
 
-    map<string, Xapian::termcount>::const_iterator j;
+    std::map<string, Xapian::termcount>::const_iterator j;
     for (j = wordfreq_changes.begin(); j != wordfreq_changes.end(); ++j) {
-	string key = "W" + j->first;
+	std::string key = "W" + j->first;
 	Xapian::termcount wordfreq = j->second;
 	if (wordfreq) {
-	    string tag;
+	    std::string tag;
 	    pack_uint_last(tag, wordfreq);
 	    add(key, tag);
 	    if (wordfreq > wordfreq_upper_bound)
@@ -110,7 +110,7 @@
 }
 
 void
-GlassSpellingTable::toggle_fragment(fragment frag, const string & word)
+GlassSpellingTable::toggle_fragment(fragment frag, const std::string & word)
 {
     auto i = termlist_deltas.find(frag);
     if (i == termlist_deltas.end()) {
@@ -126,11 +126,11 @@
 }
 
 void
-GlassSpellingTable::add_word(const string & word, Xapian::termcount freqinc)
+GlassSpellingTable::add_word(const std::string & word, Xapian::termcount freqinc)
 {
     if (word.size() <= 1) return;
 
-    map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
+    std::map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	// Word "word" already exists and has been modified.
 	if (i->second) {
@@ -141,8 +141,8 @@
 	// we need to execute the code below to re-add trigrams for it.
 	i->second = freqinc;
     } else {
-	string key = "W" + word;
-	string data;
+	std::string key = "W" + word;
+	std::string data;
 	if (get_exact_entry(key, data)) {
 	    // Word "word" already exists, so increment its count.
 	    Xapian::termcount freq;
@@ -161,11 +161,11 @@
 }
 
 void
-GlassSpellingTable::remove_word(const string & word, Xapian::termcount freqdec)
+GlassSpellingTable::remove_word(const std::string & word, Xapian::termcount freqdec)
 {
     if (word.size() <= 1) return;
 
-    map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
+    std::map<string, Xapian::termcount>::iterator i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	if (i->second == 0) {
 	    // Word has already been deleted.
@@ -180,8 +180,8 @@
 	// Mark word as deleted.
 	i->second = 0;
     } else {
-	string key = "W" + word;
-	string data;
+	std::string key = "W" + word;
+	std::string data;
 	if (!get_exact_entry(key, data)) {
 	    // This word doesn't exist.
 	    return;
@@ -205,7 +205,7 @@
 }
 
 void
-GlassSpellingTable::toggle_word(const string & word)
+GlassSpellingTable::toggle_word(const std::string & word)
 {
     fragment buf;
     // Head:
@@ -255,7 +255,7 @@
 };
 
 TermList *
-GlassSpellingTable::open_termlist(const string & word)
+GlassSpellingTable::open_termlist(const std::string & word)
 {
     // This should have been handled by Database::get_spelling_suggestion().
     AssertRel(word.size(),>,1);
@@ -266,9 +266,9 @@
 
     // Build a priority queue of TermList objects which returns those of
     // greatest approximate size first.
-    priority_queue<TermList*, vector<TermList*>, TermListGreaterApproxSize> pq;
+    priority_queue<TermList*, std::vector<TermList*>, TermListGreaterApproxSize> pq;
     try {
-	string data;
+	std::string data;
 	fragment buf;
 
 	// Head:
@@ -371,17 +371,17 @@
 }
 
 Xapian::doccount
-GlassSpellingTable::get_word_frequency(const string & word) const
+GlassSpellingTable::get_word_frequency(const std::string & word) const
 {
-    map<string, Xapian::termcount>::const_iterator i;
+    std::map<string, Xapian::termcount>::const_iterator i;
     i = wordfreq_changes.find(word);
     if (i != wordfreq_changes.end()) {
 	// Modified frequency for word:
 	return i->second;
     }
 
-    string key = "W" + word;
-    string data;
+    std::string key = "W" + word;
+    std::string data;
     if (get_exact_entry(key, data)) {
 	// Word "word" already exists.
 	Xapian::termcount freq;
@@ -444,7 +444,7 @@
 }
 
 TermList *
-GlassSpellingTermList::skip_to(const string & term)
+GlassSpellingTermList::skip_to(const std::string & term)
 {
     while (!data.empty() && current_term < term) {
 	(void)GlassSpellingTermList::next();
diff -ur xapian-core-1.4.21/backends/glass/glass_spellingwordslist.cc xapian-core-1.4.21/backends/glass/glass_spellingwordslist.cc
--- xapian-core-1.4.21/backends/glass/glass_spellingwordslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_spellingwordslist.cc	2022-11-08 16:44:15.376461870 +0100
@@ -81,7 +81,7 @@
 }
 
 TermList *
-GlassSpellingWordsList::skip_to(const string &tname)
+GlassSpellingWordsList::skip_to(const std::string &tname)
 {
     LOGCALL(DB, TermList *, "GlassSpellingWordsList::skip_to", tname);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/glass/glass_synonym.cc xapian-core-1.4.21/backends/glass/glass_synonym.cc
--- xapian-core-1.4.21/backends/glass/glass_synonym.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_synonym.cc	2022-11-08 16:44:15.352461955 +0100
@@ -47,11 +47,11 @@
     if (last_synonyms.empty()) {
 	del(last_term);
     } else {
-	string tag;
+	std::string tag;
 
 	set<string>::const_iterator i;
 	for (i = last_synonyms.begin(); i != last_synonyms.end(); ++i) {
-	    const string & synonym = *i;
+	    const std::string & synonym = *i;
 	    tag += uint8_t(synonym.size() ^ MAGIC_XOR_VALUE);
 	    tag += synonym;
 	}
@@ -63,13 +63,13 @@
 }
 
 void
-GlassSynonymTable::add_synonym(const string & term, const string & synonym)
+GlassSynonymTable::add_synonym(const std::string & term, const std::string & synonym)
 {
     if (last_term != term) {
 	merge_changes();
 	last_term = term;
 
-	string tag;
+	std::string tag;
 	if (get_exact_entry(term, tag)) {
 	    const char * p = tag.data();
 	    const char * end = p + tag.size();
@@ -89,13 +89,13 @@
 }
 
 void
-GlassSynonymTable::remove_synonym(const string & term, const string & synonym)
+GlassSynonymTable::remove_synonym(const std::string & term, const std::string & synonym)
 {
     if (last_term != term) {
 	merge_changes();
 	last_term = term;
 
-	string tag;
+	std::string tag;
 	if (get_exact_entry(term, tag)) {
 	    const char * p = tag.data();
 	    const char * end = p + tag.size();
@@ -115,7 +115,7 @@
 }
 
 void
-GlassSynonymTable::clear_synonyms(const string & term)
+GlassSynonymTable::clear_synonyms(const std::string & term)
 {
     // We don't actually ever need to merge_changes() here, but it's quite
     // likely that someone might clear_synonyms() and then add_synonym() for
@@ -131,9 +131,9 @@
 }
 
 TermList *
-GlassSynonymTable::open_termlist(const string & term)
+GlassSynonymTable::open_termlist(const std::string & term)
 {
-    vector<string> synonyms;
+    std::vector<string> synonyms;
 
     if (last_term == term) {
 	if (last_synonyms.empty()) return NULL;
@@ -144,7 +144,7 @@
 	    synonyms.push_back(*i);
 	}
     } else {
-	string tag;
+	std::string tag;
 	if (!get_exact_entry(term, tag)) return NULL;
 
 	const char * p = tag.data();
@@ -203,7 +203,7 @@
 }
 
 TermList *
-GlassSynonymTermList::skip_to(const string &tname)
+GlassSynonymTermList::skip_to(const std::string &tname)
 {
     LOGCALL(DB, TermList *, "GlassSynonymTermList::skip_to", tname);
     Assert(!at_end());
diff -ur xapian-core-1.4.21/backends/glass/glass_synonym.h xapian-core-1.4.21/backends/glass/glass_synonym.h
--- xapian-core-1.4.21/backends/glass/glass_synonym.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_synonym.h	2022-11-08 16:44:00.924513246 +0100
@@ -133,12 +133,12 @@
     GlassCursor * cursor;
 
     /// The prefix to restrict the terms to.
-    string prefix;
+    std::string prefix;
 
   public:
     GlassSynonymTermList(Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> database_,
 			 GlassCursor * cursor_,
-			 const string & prefix_)
+			 const std::string & prefix_)
 	    : database(database_), cursor(cursor_), prefix(prefix_)
     {
 	// Position the cursor on the highest key before the first key we want,
@@ -160,7 +160,7 @@
      *  Either next() or skip_to() must have been called before this
      *  method can be called.
      */
-    string get_termname() const;
+    std::string get_termname() const;
 
     /// Return the term frequency for the term at the current position.
     Xapian::doccount get_termfreq() const;
@@ -169,7 +169,7 @@
     TermList * next();
 
     /// Advance to the first term which is >= tname.
-    TermList * skip_to(const string &tname);
+    TermList * skip_to(const std::string &tname);
 
     /// True if we're off the end of the list
     bool at_end() const;
diff -ur xapian-core-1.4.21/backends/glass/glass_table.cc xapian-core-1.4.21/backends/glass/glass_table.cc
--- xapian-core-1.4.21/backends/glass/glass_table.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_table.cc	2022-11-08 16:44:15.372461885 +0100
@@ -170,7 +170,7 @@
     if (GET_LEVEL(p) != LEVEL_FREELIST) {
 	int dir_end = DIR_END(p);
 	if (rare(dir_end < DIR_START || unsigned(dir_end) > block_size)) {
-	    string msg("dir_end invalid in block ");
+	    std::string msg("dir_end invalid in block ");
 	    msg += str(n);
 	    throw Xapian::DatabaseCorruptError(msg);
 	}
@@ -256,7 +256,7 @@
 	return; // FIXME
     }
 
-    string buf;
+    std::string buf;
     buf += char(v);
     // Write the block number to the file
     pack_uint(buf, n);
@@ -339,7 +339,7 @@
     }
 
     if (rare(j != GET_LEVEL(p))) {
-	string msg = "Expected block ";
+	std::string msg = "Expected block ";
 	msg += str(n);
 	msg += " to be level ";
 	msg += str(j);
@@ -1244,7 +1244,7 @@
 K set accordingly. c is set to 1.
 */
 
-void GlassTable::form_key(const string & key) const
+void GlassTable::form_key(const std::string & key) const
 {
     LOGCALL_VOID(DB, "GlassTable::form_key", key);
     kt.form_key(key);
@@ -1274,7 +1274,7 @@
 */
 
 void
-GlassTable::add(const string &key, string tag, bool already_compressed)
+GlassTable::add(const std::string &key, std::string tag, bool already_compressed)
 {
     LOGCALL_VOID(DB, "GlassTable::add", key | tag | already_compressed);
     Assert(writable);
@@ -1389,7 +1389,7 @@
 */
 
 bool
-GlassTable::del(const string &key)
+GlassTable::del(const std::string &key)
 {
     LOGCALL(DB, bool, "GlassTable::del", key);
     Assert(writable);
@@ -1425,7 +1425,7 @@
 }
 
 bool
-GlassTable::readahead_key(const string &key) const
+GlassTable::readahead_key(const std::string &key) const
 {
     LOGCALL(DB, bool, "GlassTable::readahead_key", key);
     Assert(!key.empty());
@@ -1468,7 +1468,7 @@
 }
 
 bool
-GlassTable::get_exact_entry(const string &key, string & tag) const
+GlassTable::get_exact_entry(const std::string &key, std::string & tag) const
 {
     LOGCALL(DB, bool, "GlassTable::get_exact_entry", key | tag);
     Assert(!key.empty());
@@ -1491,7 +1491,7 @@
 }
 
 bool
-GlassTable::key_exists(const string &key) const
+GlassTable::key_exists(const std::string &key) const
 {
     LOGCALL(DB, bool, "GlassTable::key_exists", key);
     Assert(!key.empty());
@@ -1504,7 +1504,7 @@
 }
 
 bool
-GlassTable::read_tag(Glass::Cursor * C_, string *tag, bool keep_compressed) const
+GlassTable::read_tag(Glass::Cursor * C_, std::string *tag, bool keep_compressed) const
 {
     LOGCALL(DB, bool, "GlassTable::read_tag", Literal("C_") | tag | keep_compressed);
 
@@ -1581,7 +1581,7 @@
     item_count =	   root_info->get_num_entries();
     faked_root_block = root_info->get_root_is_fake();
     sequential =	   root_info->get_sequential();
-    const string & fl_serialised = root_info->get_free_list();
+    const std::string & fl_serialised = root_info->get_free_list();
     if (!fl_serialised.empty()) {
 	if (!free_list.unpack(fl_serialised))
 	    throw Xapian::DatabaseCorruptError("Bad freelist metadata");
@@ -1674,7 +1674,7 @@
 		revision_number = rev;
 		return;
 	    }
-	    string message((rev == 0) ? "Couldn't create " : "Couldn't open ");
+	    std::string message((rev == 0) ? "Couldn't create " : "Couldn't open ");
 	    message += name;
 	    message += GLASS_TABLE_EXTENSION" read/write";
 	    throw Xapian::DatabaseOpeningError(message, errno);
@@ -1693,7 +1693,7 @@
     seq_count = SEQ_START_POINT;
 }
 
-GlassTable::GlassTable(const char * tablename_, const string & path_,
+GlassTable::GlassTable(const char * tablename_, const std::string & path_,
 		       bool readonly_, bool lazy_)
 	: tablename(tablename_),
 	  revision_number(0),
@@ -1904,7 +1904,7 @@
 	free_list.commit(this, block_size);
 
 	// Save the freelist details into the root_info.
-	string serialised;
+	std::string serialised;
 	free_list.pack(serialised);
 	root_info->set_free_list(serialised);
 
@@ -1946,7 +1946,7 @@
     item_count =       root_info.get_num_entries();
     faked_root_block = root_info.get_root_is_fake();
     sequential =       root_info.get_sequential();
-    const string & fl_serialised = root_info.get_free_list();
+    const std::string & fl_serialised = root_info.get_free_list();
     if (!fl_serialised.empty()) {
 	if (!free_list.unpack(fl_serialised))
 	    throw Xapian::DatabaseCorruptError("Bad freelist metadata");
@@ -1992,7 +1992,7 @@
 		revision_number = rev;
 		return;
 	    }
-	    string message("Couldn't open ");
+	    std::string message("Couldn't open ");
 	    message += name;
 	    message += GLASS_TABLE_EXTENSION" to read";
 	    throw Xapian::DatabaseOpeningError(message, errno);
diff -ur xapian-core-1.4.21/backends/glass/glass_table.h xapian-core-1.4.21/backends/glass/glass_table.h
--- xapian-core-1.4.21/backends/glass/glass_table.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_table.h	2022-11-08 16:44:00.936513203 +0100
@@ -484,7 +484,7 @@
      */
     void close(bool permanent = false);
 
-    bool readahead_key(const string &key) const;
+    bool readahead_key(const std::string &key) const;
 
     /** Determine whether the btree exists on disk.
      */
@@ -730,7 +730,7 @@
     /// Throw an exception indicating that the database is closed.
     XAPIAN_NORETURN(static void throw_database_closed());
 
-    string get_path() const {
+    std::string get_path() const {
 	return name + GLASS_TABLE_EXTENSION;
     }
 
@@ -926,8 +926,8 @@
    when they are preordered by their keys. This is therefore the piece
    of code that needs to be followed to arrange for the preordering.
 
-   Note that keys have two parts - a string value and a "component_of" count.
-   If the string values are equal, the comparison is made based on
+   Note that keys have two parts - a std::string value and a "component_of" count.
+   If the std::string values are equal, the comparison is made based on
    "component_of".
 */
 
diff -ur xapian-core-1.4.21/backends/glass/glass_termlist.cc xapian-core-1.4.21/backends/glass/glass_termlist.cc
--- xapian-core-1.4.21/backends/glass/glass_termlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_termlist.cc	2022-11-08 16:44:15.368461899 +0100
@@ -187,7 +187,7 @@
 }
 
 TermList *
-GlassTermList::skip_to(const string & term)
+GlassTermList::skip_to(const std::string & term)
 {
     LOGCALL(API, TermList *, "GlassTermList::skip_to", term);
     while (pos != NULL && current_term < term) {
diff -ur xapian-core-1.4.21/backends/glass/glass_termlisttable.cc xapian-core-1.4.21/backends/glass/glass_termlisttable.cc
--- xapian-core-1.4.21/backends/glass/glass_termlisttable.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_termlisttable.cc	2022-11-08 16:44:15.368461899 +0100
@@ -51,13 +51,13 @@
 	return;
     }
 
-    string tag;
+    std::string tag;
     pack_uint(tag, doclen);
 
     Xapian::TermIterator t = doc.termlist_begin();
     if (t != doc.termlist_end()) {
 	pack_uint(tag, termlist_size);
-	string prev_term = *t;
+	std::string prev_term = *t;
 
 	tag += char(prev_term.size());
 	tag += prev_term;
@@ -65,7 +65,7 @@
 	--termlist_size;
 
 	while (++t != doc.termlist_end()) {
-	    const string & term = *t;
+	    const std::string & term = *t;
 	    // If there's a shared prefix with the previous term, we don't
 	    // store it explicitly, but just store the length of the shared
 	    // prefix.  In general, this is a big win.
diff -ur xapian-core-1.4.21/backends/glass/glass_valuelist.cc xapian-core-1.4.21/backends/glass/glass_valuelist.cc
--- xapian-core-1.4.21/backends/glass/glass_valuelist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_valuelist.cc	2022-11-08 16:44:15.376461870 +0100
@@ -37,7 +37,7 @@
     if (!first_did) return false;
 
     cursor->read_tag();
-    const string & tag = cursor->current_tag;
+    const std::string & tag = cursor->current_tag;
     reader.assign(tag.data(), tag.size(), first_did);
     return true;
 }
@@ -165,7 +165,7 @@
 string
 GlassValueList::get_description() const
 {
-    string desc("GlassValueList(slot=");
+    std::string desc("GlassValueList(slot=");
     desc += str(slot);
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/backends/glass/glass_values.cc xapian-core-1.4.21/backends/glass/glass_values.cc
--- xapian-core-1.4.21/backends/glass/glass_values.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_values.cc	2022-11-08 16:44:15.360461927 +0100
@@ -52,7 +52,7 @@
     // Add an extra character so that it can't clash with a termlist entry key
     // and will sort just after the corresponding termlist entry key.
     // FIXME: should we store this in the *same entry* as the list of terms?
-    string key;
+    std::string key;
     pack_uint_preserving_sort(key, did);
     key += '\0';
     RETURN(key);
@@ -63,7 +63,7 @@
 make_valuestats_key(Xapian::valueno slot)
 {
     LOGCALL_STATIC(DB, string, "make_valuestats_key", slot);
-    string key("\0\xd0", 2);
+    std::string key("\0\xd0", 2);
     pack_uint_last(key, slot);
     RETURN(key);
 }
@@ -131,11 +131,11 @@
 
 void
 GlassValueManager::add_value(Xapian::docid did, Xapian::valueno slot,
-			     const string & val)
+			     const std::string & val)
 {
     auto i = changes.find(slot);
     if (i == changes.end()) {
-	i = changes.insert(make_pair(slot, map<Xapian::docid, string>())).first;
+	i = changes.insert(make_pair(slot, std::map<Xapian::docid, string>())).first;
     }
     i->second[did] = val;
 }
@@ -145,7 +145,7 @@
 {
     auto i = changes.find(slot);
     if (i == changes.end()) {
-	i = changes.insert(make_pair(slot, map<Xapian::docid, string>())).first;
+	i = changes.insert(make_pair(slot, std::map<Xapian::docid, string>())).first;
     }
     i->second[did] = string();
 }
@@ -153,7 +153,7 @@
 Xapian::docid
 GlassValueManager::get_chunk_containing_did(Xapian::valueno slot,
 					    Xapian::docid did,
-					    string &chunk) const
+					    std::string &chunk) const
 {
     LOGCALL(DB, Xapian::docid, "GlassValueManager::get_chunk_containing_did", slot | did | chunk);
     if (!cursor.get())
@@ -198,11 +198,11 @@
 
     Xapian::valueno slot;
 
-    string ctag;
+    std::string ctag;
 
     ValueChunkReader reader;
 
-    string tag;
+    std::string tag;
 
     Xapian::docid prev_did;
 
@@ -212,7 +212,7 @@
 
     Xapian::docid last_allowed_did;
 
-    void append_to_stream(Xapian::docid did, const string & value) {
+    void append_to_stream(Xapian::docid did, const std::string & value) {
 	Assert(did);
 	if (tag.empty()) {
 	    new_first_did = did;
@@ -250,13 +250,13 @@
 	write_tag();
     }
 
-    void update(Xapian::docid did, const string & value) {
+    void update(Xapian::docid did, const std::string & value) {
 	if (last_allowed_did && did > last_allowed_did) {
 	    // The next change needs to go in a later existing chunk than the
 	    // one we're currently updating, so we copy over the rest of the
 	    // entries from the current chunk, write out the updated chunk and
 	    // drop through to the case below will read in that later chunk.
-	    // FIXME: use some string splicing magic instead of this loop.
+	    // FIXME: use some std::string splicing magic instead of this loop.
 	    while (!reader.at_end()) {
 		// last_allowed_did should be an upper bound for this chunk.
 		AssertRel(reader.get_docid(),<=,last_allowed_did);
@@ -295,7 +295,7 @@
 		reader.assign(ctag.data(), ctag.size(), first_did);
 	    }
 	    if (cursor->next()) {
-		const string & key = cursor->current_key;
+		const std::string & key = cursor->current_key;
 		Xapian::docid next_first_did = docid_from_key(slot, key);
 		if (next_first_did) last_allowed_did = next_first_did - 1;
 		Assert(last_allowed_did);
@@ -325,7 +325,7 @@
 {
     if (termlist_table->is_open()) {
 	for (auto i : slots) {
-	    string key = make_slot_key(i.first);
+	    std::string key = make_slot_key(i.first);
 	    const string& enc = i.second;
 	    if (!enc.empty()) {
 		termlist_table->add(key, enc);
@@ -339,7 +339,7 @@
     for (auto i : changes) {
 	Xapian::valueno slot = i.first;
 	Glass::ValueUpdater updater(postlist_table, slot);
-	const map<Xapian::docid, string>& slot_changes = i.second;
+	const std::map<Xapian::docid, string>& slot_changes = i.second;
 	for (auto j : slot_changes) {
 	    updater.update(j.first, j.second);
 	}
@@ -349,16 +349,16 @@
 
 void
 GlassValueManager::add_document(Xapian::docid did, const Xapian::Document &doc,
-				map<Xapian::valueno, ValueStats> & value_stats)
+				std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     // FIXME: Use BitWriter and interpolative coding?  Or is it not worthwhile
     // for this?
-    string slots_used;
+    std::string slots_used;
     Xapian::valueno prev_slot = static_cast<Xapian::valueno>(-1);
     Xapian::ValueIterator it = doc.values_begin();
     while (it != doc.values_end()) {
 	Xapian::valueno slot = it.get_valueno();
-	string value = *it;
+	std::string value = *it;
 	Assert(!value.empty());
 
 	// Update the statistics.
@@ -401,11 +401,11 @@
 
 void
 GlassValueManager::delete_document(Xapian::docid did,
-				   map<Xapian::valueno, ValueStats> & value_stats)
+				   std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     Assert(termlist_table->is_open());
-    map<Xapian::docid, string>::iterator it = slots.find(did);
-    string s;
+    std::map<Xapian::docid, string>::iterator it = slots.find(did);
+    std::string s;
     if (it != slots.end()) {
 	swap(s, it->second);
     } else {
@@ -446,7 +446,7 @@
 void
 GlassValueManager::replace_document(Xapian::docid did,
 				    const Xapian::Document &doc,
-				    map<Xapian::valueno, ValueStats> & value_stats)
+				    std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     if (doc.get_docid() == did) {
 	// If we're replacing a document with itself, but the optimisation for
@@ -478,7 +478,7 @@
     }
 
     // Read it from the table.
-    string chunk;
+    std::string chunk;
     Xapian::docid first_did;
     first_did = get_chunk_containing_did(slot, did, chunk);
     if (first_did == 0) return string();
@@ -490,7 +490,7 @@
 }
 
 void
-GlassValueManager::get_all_values(map<Xapian::valueno, string> & values,
+GlassValueManager::get_all_values(std::map<Xapian::valueno, string> & values,
 				  Xapian::docid did) const
 {
     Assert(values.empty());
@@ -502,8 +502,8 @@
 	    GlassTable::throw_database_closed();
 	throw Xapian::FeatureUnavailableError("Database has no termlist");
     }
-    map<Xapian::docid, string>::const_iterator i = slots.find(did);
-    string s;
+    std::map<Xapian::docid, string>::const_iterator i = slots.find(did);
+    std::string s;
     if (i != slots.end()) {
 	s = i->second;
     } else {
@@ -539,7 +539,7 @@
 {
     LOGCALL_VOID(DB, "GlassValueManager::get_value_stats", slot | Literal("[stats]"));
 
-    string tag;
+    std::string tag;
     if (postlist_table->get_exact_entry(make_valuestats_key(slot), tag)) {
 	const char * pos = tag.data();
 	const char * end = pos + tag.size();
@@ -571,15 +571,15 @@
 }
 
 void
-GlassValueManager::set_value_stats(map<Xapian::valueno, ValueStats> & value_stats)
+GlassValueManager::set_value_stats(std::map<Xapian::valueno, ValueStats> & value_stats)
 {
     LOGCALL_VOID(DB, "GlassValueManager::set_value_stats", value_stats);
-    map<Xapian::valueno, ValueStats>::const_iterator i;
+    std::map<Xapian::valueno, ValueStats>::const_iterator i;
     for (i = value_stats.begin(); i != value_stats.end(); ++i) {
-	string key = make_valuestats_key(i->first);
+	std::string key = make_valuestats_key(i->first);
 	const ValueStats & stats = i->second;
 	if (stats.freq != 0) {
-	    string new_value;
+	    std::string new_value;
 	    pack_uint(new_value, stats.freq);
 	    pack_string(new_value, stats.lower_bound);
 	    // We don't store or count empty values, so neither of the bounds
diff -ur xapian-core-1.4.21/backends/glass/glass_version.cc xapian-core-1.4.21/backends/glass/glass_version.cc
--- xapian-core-1.4.21/backends/glass/glass_version.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_version.cc	2022-11-08 16:44:15.356461942 +0100
@@ -78,7 +78,7 @@
 {
     offset = lseek(fd, 0, SEEK_CUR);
     if (rare(offset < 0)) {
-	string msg = "lseek failed on file descriptor ";
+	std::string msg = "lseek failed on file descriptor ";
 	msg += str(fd);
 	throw Xapian::DatabaseOpeningError(msg, errno);
     }
@@ -100,17 +100,17 @@
     int fd_in;
     if (single_file()) {
 	if (rare(lseek(fd, offset, SEEK_SET) < 0)) {
-	    string msg = "Failed to rewind file descriptor ";
+	    std::string msg = "Failed to rewind file descriptor ";
 	    msg += str(fd);
 	    throw Xapian::DatabaseOpeningError(msg, errno);
 	}
 	fd_in = fd;
     } else {
-	string filename = db_dir;
+	std::string filename = db_dir;
 	filename += "/iamglass";
 	fd_in = posixy_open(filename.c_str(), O_RDONLY|O_BINARY);
 	if (rare(fd_in < 0)) {
-	    string msg = filename;
+	    std::string msg = filename;
 	    msg += ": Failed to open glass revision file for reading";
 	    if (errno == ENOENT || errno == ENOTDIR) {
 		throw Xapian::DatabaseNotFoundError(msg, errno);
@@ -133,7 +133,7 @@
     version <<= 8;
     version |= static_cast<unsigned char>(buf[GLASS_VERSION_MAGIC_LEN + 1]);
     if (version != GLASS_FORMAT_VERSION) {
-	string msg;
+	std::string msg;
 	if (!single_file()) {
 	    msg = db_dir;
 	    msg += ": ";
@@ -272,7 +272,7 @@
 {
     LOGCALL(DB, const string, "GlassVersion::write", new_rev|flags);
 
-    string s(GLASS_VERSION_MAGIC, GLASS_VERSION_MAGIC_AND_VERSION_LEN);
+    std::string s(GLASS_VERSION_MAGIC, GLASS_VERSION_MAGIC_AND_VERSION_LEN);
     s.append(uuid.data(), uuid.BINARY_SIZE);
 
     pack_uint(s, new_rev);
@@ -285,7 +285,7 @@
     serialise_stats();
     s += serialised_stats;
 
-    string tmpfile;
+    std::string tmpfile;
     if (!single_file()) {
 	tmpfile = db_dir;
 	// In dangerous mode, just write the new version file in place.
@@ -312,7 +312,7 @@
     }
 
     if (changes) {
-	string changes_buf;
+	std::string changes_buf;
 	changes_buf += '\xfe';
 	pack_uint(changes_buf, new_rev);
 	pack_uint(changes_buf, s.size());
@@ -324,7 +324,7 @@
 }
 
 bool
-GlassVersion::sync(const string & tmpfile,
+GlassVersion::sync(const std::string & tmpfile,
 		   glass_revision_number_t new_rev, int flags)
 {
     Assert(new_rev > rev || rev == 0);
diff -ur xapian-core-1.4.21/backends/glass/glass_version.h xapian-core-1.4.21/backends/glass/glass_version.h
--- xapian-core-1.4.21/backends/glass/glass_version.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/glass/glass_version.h	2022-11-08 16:44:00.924513246 +0100
@@ -86,7 +86,7 @@
 
 /** The GlassVersion class manages the revision files.
  *
- *  The "iamglass" file (currently) contains a "magic" string identifying
+ *  The "iamglass" file (currently) contains a "magic" std::string identifying
  *  that this is a glass database, a database format version number, the UUID
  *  of the database, the revision of the database, and the root block info for
  *  each table.
@@ -199,7 +199,7 @@
 	return uuid.data();
     }
 
-    /// Return UUID in the standard 36 character string format.
+    /// Return UUID in the standard 36 character std::string format.
     std::string get_uuid_string() const {
 	return uuid.to_string();
     }
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.cc xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.cc
--- xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.cc	2022-11-08 16:44:15.332462027 +0100
@@ -45,10 +45,10 @@
 }
 
 TermList *
-InMemoryAllTermsList::skip_to(const string &tname_)
+InMemoryAllTermsList::skip_to(const std::string &tname_)
 {
     if (database->is_closed()) InMemoryDatabase::throw_database_closed();
-    string tname(tname_);
+    std::string tname(tname_);
     Assert(it != tmap->end());
     if (!it->first.empty()) {
 	// Don't skip backwards.
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.h xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.h
--- xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_alltermslist.h	2022-11-08 16:44:00.908513303 +0100
@@ -42,7 +42,7 @@
 
     Xapian::Internal::intrusive_ptr<const InMemoryDatabase> database;
 
-    string prefix;
+    std::string prefix;
 
   public:
     /// Constructor.
@@ -55,12 +55,12 @@
     }
 
     // Gets current termname
-    string get_termname() const;
+    std::string get_termname() const;
 
     // Get num of docs indexed by term
     Xapian::doccount get_termfreq() const;
 
-    TermList * skip_to(const string &tname);
+    TermList * skip_to(const std::string &tname);
 
     /** next() causes the AllTermsList to move to the next term in the list.
      */
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_database.cc xapian-core-1.4.21/backends/inmemory/inmemory_database.cc
--- xapian-core-1.4.21/backends/inmemory/inmemory_database.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_database.cc	2022-11-08 16:44:15.332462027 +0100
@@ -49,7 +49,7 @@
 InMemoryTerm::add_posting(const InMemoryPosting & post)
 {
     // Add document to right place in list
-    vector<InMemoryPosting>::iterator p;
+    std::vector<InMemoryPosting>::iterator p;
     p = lower_bound(docs.begin(), docs.end(),
 		    post, InMemoryPostingLessThan());
     if (p == docs.end() || InMemoryPostingLessThan()(post, *p)) {
@@ -65,7 +65,7 @@
 InMemoryDoc::add_posting(const InMemoryTermEntry & post)
 {
     // Add document to right place in list
-    vector<InMemoryTermEntry>::iterator p;
+    std::vector<InMemoryTermEntry>::iterator p;
     p = lower_bound(terms.begin(), terms.end(),
 		    post, InMemoryTermEntryLessThan());
     if (p == terms.end() || InMemoryTermEntryLessThan()(post, *p)) {
@@ -93,7 +93,7 @@
     while (pos != end && !pos->valid) ++pos;
     if (pos != end) {
 	auto first_wdf = (*pos).wdf;
-	wdf_upper_bound = max(first_wdf, imterm.collection_freq - first_wdf);
+	wdf_upper_bound = std::max(first_wdf, imterm.collection_freq - first_wdf);
     }
 }
 
@@ -279,7 +279,7 @@
 }
 
 TermList *
-InMemoryTermList::skip_to(const string & term)
+InMemoryTermList::skip_to(const std::string & term)
 {
     if (rare(db->is_closed()))
 	InMemoryDatabase::throw_database_closed();
@@ -457,13 +457,13 @@
 }
 
 LeafPostList *
-InMemoryDatabase::open_post_list(const string & tname) const
+InMemoryDatabase::open_post_list(const std::string & tname) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     if (tname.empty()) {
 	return new InMemoryAllDocsPostList(this);
     }
-    map<string, InMemoryTerm>::const_iterator i = postlists.find(tname);
+    std::map<string, InMemoryTerm>::const_iterator i = postlists.find(tname);
     if (i == postlists.end() || i->second.term_freq == 0) {
 	i = postlists.begin();
 	// Check that our dummy entry for string() is present.
@@ -480,12 +480,12 @@
 }
 
 void
-InMemoryDatabase::get_freqs(const string & term,
+InMemoryDatabase::get_freqs(const std::string & term,
 			    Xapian::doccount * termfreq_ptr,
 			    Xapian::termcount * collfreq_ptr) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
-    map<string, InMemoryTerm>::const_iterator i = postlists.find(term);
+    std::map<string, InMemoryTerm>::const_iterator i = postlists.find(term);
     if (i != postlists.end()) {
 	if (termfreq_ptr)
 	    *termfreq_ptr = i->second.term_freq;
@@ -503,7 +503,7 @@
 InMemoryDatabase::get_value_freq(Xapian::valueno slot) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
-    map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
+    std::map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
     if (i == valuestats.end()) return 0;
     return i->second.freq;
 }
@@ -512,7 +512,7 @@
 InMemoryDatabase::get_value_lower_bound(Xapian::valueno slot) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
-    map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
+    std::map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
     if (i == valuestats.end()) return string();
     return i->second.lower_bound;
 }
@@ -521,7 +521,7 @@
 InMemoryDatabase::get_value_upper_bound(Xapian::valueno slot) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
-    map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
+    std::map<Xapian::valueno, ValueStats>::const_iterator i = valuestats.find(slot);
     if (i == valuestats.end()) return string();
     return i->second.upper_bound;
 }
@@ -602,14 +602,14 @@
 InMemoryDatabase::get_metadata(const std::string & key) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
-    map<string, string>::const_iterator i = metadata.find(key);
+    std::map<string, string>::const_iterator i = metadata.find(key);
     if (i == metadata.end())
 	return string();
     return i->second;
 }
 
 TermList *
-InMemoryDatabase::open_metadata_keylist(const string &) const
+InMemoryDatabase::open_metadata_keylist(const std::string &) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     if (metadata.empty()) return NULL;
@@ -631,7 +631,7 @@
 
 Xapian::termcount
 InMemoryDatabase::positionlist_count(Xapian::docid did,
-				     const string & tname) const
+				     const std::string & tname) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     if (!doc_exists(did)) {
@@ -651,7 +651,7 @@
 
 PositionList *
 InMemoryDatabase::open_position_list(Xapian::docid did,
-				     const string & tname) const
+				     const std::string & tname) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     if (usual(doc_exists(did))) {
@@ -670,7 +670,7 @@
 
 void
 InMemoryDatabase::add_values(Xapian::docid did,
-			     const map<Xapian::valueno, string> &values_)
+			     const std::map<Xapian::valueno, string> &values_)
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     if (did > valuelists.size()) {
@@ -679,10 +679,10 @@
     valuelists[did - 1] = values_;
 
     // Update the statistics.
-    map<Xapian::valueno, string>::const_iterator j;
+    std::map<Xapian::valueno, string>::const_iterator j;
     for (j = values_.begin(); j != values_.end(); ++j) {
-	std::pair<map<Xapian::valueno, ValueStats>::iterator, bool> i;
-	i = valuestats.insert(make_pair(j->first, ValueStats()));
+	std::pair<std::map<Xapian::valueno, ValueStats>::iterator, bool> i;
+	i = valuestats.insert(std::make_pair(j->first, ValueStats()));
 
 	// Now, modify the stored statistics.
 	if ((i.first->second.freq)++ == 0) {
@@ -724,9 +724,9 @@
     }
     termlists[did - 1].is_valid = false;
     doclists[did - 1] = string();
-    map<Xapian::valueno, string>::const_iterator j;
+    std::map<Xapian::valueno, string>::const_iterator j;
     for (j = valuelists[did - 1].begin(); j != valuelists[did - 1].end(); ++j) {
-	map<Xapian::valueno, ValueStats>::iterator i;
+	std::map<Xapian::valueno, ValueStats>::iterator i;
 	i = valuestats.find(j->first);
 	if (--(i->second.freq) == 0) {
 	    i->second.lower_bound.resize(0);
@@ -742,11 +742,11 @@
     // InMemory structure without being very inefficient.
     if (totdocs == 0) positions_present = false;
 
-    vector<InMemoryTermEntry>::const_iterator i;
+    std::vector<InMemoryTermEntry>::const_iterator i;
     for (i = termlists[did - 1].terms.begin();
 	 i != termlists[did - 1].terms.end();
 	 ++i) {
-	map<string, InMemoryTerm>::iterator t = postlists.find(i->tname);
+	std::map<string, InMemoryTerm>::iterator t = postlists.find(i->tname);
 	Assert(t != postlists.end());
 	t->second.collection_freq -= i->wdf;
 	--t->second.term_freq;
@@ -774,9 +774,9 @@
     if (closed) InMemoryDatabase::throw_database_closed();
 
     if (doc_exists(did)) {
-	map<Xapian::valueno, string>::const_iterator j;
+	std::map<Xapian::valueno, string>::const_iterator j;
 	for (j = valuelists[did - 1].begin(); j != valuelists[did - 1].end(); ++j) {
-	    map<Xapian::valueno, ValueStats>::iterator i;
+	    std::map<Xapian::valueno, ValueStats>::iterator i;
 	    i = valuestats.find(j->first);
 	    if (--(i->second.freq) == 0) {
 		i->second.lower_bound.resize(0);
@@ -796,11 +796,11 @@
 	termlists[did - 1].is_valid = true;
     }
 
-    vector<InMemoryTermEntry>::const_iterator i;
+    std::vector<InMemoryTermEntry>::const_iterator i;
     for (i = termlists[did - 1].terms.begin();
 	 i != termlists[did - 1].terms.end();
 	 ++i) {
-	map<string, InMemoryTerm>::iterator t = postlists.find(i->tname);
+	std::map<string, InMemoryTerm>::iterator t = postlists.find(i->tname);
 	Assert(t != postlists.end());
 	t->second.collection_freq -= i->wdf;
 	--t->second.term_freq;
@@ -840,7 +840,7 @@
 InMemoryDatabase::finish_add_doc(Xapian::docid did, const Xapian::Document &document)
 {
     {
-	map<Xapian::valueno, string> values;
+	std::map<Xapian::valueno, string> values;
 	Xapian::ValueIterator k = document.values_begin();
 	for ( ; k != document.values_end(); ++k) {
 	    values.insert(make_pair(k.get_valueno(), *k));
@@ -873,19 +873,19 @@
 	postlists[*i].collection_freq += i.get_wdf();
 	++postlists[*i].term_freq;
     }
-    swap(termlists[did - 1], doc);
+    std::swap(termlists[did - 1], doc);
 
     totdocs++;
 }
 
 void
-InMemoryDatabase::make_term(const string & tname)
+InMemoryDatabase::make_term(const std::string & tname)
 {
     postlists[tname];  // Initialise, if not already there.
 }
 
 Xapian::docid
-InMemoryDatabase::make_doc(const string & docdata)
+InMemoryDatabase::make_doc(const std::string & docdata)
 {
     termlists.push_back(InMemoryDoc(true));
     doclengths.push_back(0);
@@ -897,7 +897,7 @@
 }
 
 void InMemoryDatabase::make_posting(InMemoryDoc * doc,
-				    const string & tname,
+				    const std::string & tname,
 				    Xapian::docid did,
 				    Xapian::termpos position,
 				    Xapian::termcount wdf,
@@ -934,11 +934,11 @@
 }
 
 bool
-InMemoryDatabase::term_exists(const string & tname) const
+InMemoryDatabase::term_exists(const std::string & tname) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     Assert(!tname.empty());
-    map<string, InMemoryTerm>::const_iterator i = postlists.find(tname);
+    std::map<string, InMemoryTerm>::const_iterator i = postlists.find(tname);
     if (i == postlists.end()) return false;
     return (i->second.term_freq != 0);
 }
@@ -951,7 +951,7 @@
 }
 
 TermList *
-InMemoryDatabase::open_allterms(const string & prefix) const
+InMemoryDatabase::open_allterms(const std::string & prefix) const
 {
     if (closed) InMemoryDatabase::throw_database_closed();
     return new InMemoryAllTermsList(&postlists,
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_database.h xapian-core-1.4.21/backends/inmemory/inmemory_database.h
--- xapian-core-1.4.21/backends/inmemory/inmemory_database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_database.h	2022-11-08 16:44:00.904513317 +0100
@@ -39,7 +39,7 @@
 #include "omassert.h"
 #include "noreturn.h"
 
-using namespace std;
+using std::string;
 
 // Class representing a posting (a term/doc pair, and
 // all the relevant positional information, is a single posting)
@@ -47,7 +47,7 @@
   public:
     Xapian::docid did;
     bool valid;
-    vector<Xapian::termpos> positions; // Sorted vector of positions
+    std::vector<Xapian::termpos> positions; // Sorted vector of positions
     Xapian::termcount wdf;
 
     // Merge two postings (same term/doc pair, new positional info)
@@ -57,15 +57,15 @@
 	positions.insert(positions.end(),
 			 post.positions.begin(),
 			 post.positions.end());
-	// FIXME - inefficient - use merge (and list<>)?
+	// FIXME - inefficient - use merge (and std::list<>)?
 	sort(positions.begin(), positions.end());
     }
 };
 
 class InMemoryTermEntry {
   public:
-    string tname;
-    vector<Xapian::termpos> positions; // Sorted vector of positions
+    std::string tname;
+    std::vector<Xapian::termpos> positions; // Sorted vector of positions
     Xapian::termcount wdf;
 
     // Merge two postings (same term/doc pair, new positional info)
@@ -75,7 +75,7 @@
 	positions.insert(positions.end(),
 			 post.positions.begin(),
 			 post.positions.end());
-	// FIXME - inefficient - use merge (and list<>)?
+	// FIXME - inefficient - use merge (and std::list<>)?
 	sort(positions.begin(), positions.end());
     }
 };
@@ -104,7 +104,7 @@
 class InMemoryTerm {
   public:
     // Sorted list of documents indexing this term.
-    vector<InMemoryPosting> docs;
+    std::vector<InMemoryPosting> docs;
 
     Xapian::termcount term_freq;
     Xapian::termcount collection_freq;
@@ -119,7 +119,7 @@
   public:
     bool is_valid;
     // Sorted list of terms indexing this document.
-    vector<InMemoryTermEntry> terms;
+    std::vector<InMemoryTermEntry> terms;
 
     /* Initialise invalid by default, so that resizing the termlist array
      * doesn't create valid documents. */
@@ -139,8 +139,8 @@
     friend class InMemoryDatabase;
 
   private:
-    vector<InMemoryPosting>::const_iterator pos;
-    vector<InMemoryPosting>::const_iterator end;
+    std::vector<InMemoryPosting>::const_iterator pos;
+    std::vector<InMemoryPosting>::const_iterator end;
     Xapian::doccount termfreq;
     bool started;
 
@@ -175,7 +175,7 @@
 
     Xapian::termcount get_wdf_upper_bound() const;
 
-    string get_description() const;
+    std::string get_description() const;
 };
 
 /** A PostList over all docs in an inmemory database.
@@ -211,7 +211,7 @@
 
     Xapian::termcount get_wdf_upper_bound() const;
 
-    string get_description() const;
+    std::string get_description() const;
 };
 
 // Term List
@@ -219,8 +219,8 @@
     friend class InMemoryDatabase;
 
   private:
-    vector<InMemoryTermEntry>::const_iterator pos;
-    vector<InMemoryTermEntry>::const_iterator end;
+    std::vector<InMemoryTermEntry>::const_iterator pos;
+    std::vector<InMemoryTermEntry>::const_iterator end;
     Xapian::termcount terms;
     bool started;
 
@@ -239,7 +239,7 @@
     /// Collate weighting information for the current term.
     void accumulate_stats(Xapian::Internal::ExpandStats & stats) const;
 
-    string get_termname() const;
+    std::string get_termname() const;
     // Number of occurrences of term in current doc
     Xapian::termcount get_wdf() const;
     Xapian::doccount get_termfreq() const;  // Number of docs indexed by term
@@ -260,13 +260,13 @@
     friend class InMemoryAllDocsPostList;
     friend class InMemoryDocument;
 
-    map<string, InMemoryTerm> postlists;
-    vector<InMemoryDoc> termlists;
-    vector<std::string> doclists;
-    vector<std::map<Xapian::valueno, string>> valuelists;
+    std::map<string, InMemoryTerm> postlists;
+    std::vector<InMemoryDoc> termlists;
+    std::vector<std::string> doclists;
+    std::vector<std::map<Xapian::valueno, string>> valuelists;
     std::map<Xapian::valueno, ValueStats> valuestats;
 
-    vector<Xapian::termcount> doclengths;
+    std::vector<Xapian::termcount> doclengths;
 
     std::map<string, string> metadata;
 
@@ -283,18 +283,18 @@
     InMemoryDatabase& operator=(const InMemoryDatabase &);
     InMemoryDatabase(const InMemoryDatabase &);
 
-    void make_term(const string & tname);
+    void make_term(const std::string & tname);
 
     bool doc_exists(Xapian::docid did) const;
-    Xapian::docid make_doc(const string & docdata);
+    Xapian::docid make_doc(const std::string & docdata);
 
     /* The common parts of add_doc and replace_doc */
     void finish_add_doc(Xapian::docid did, const Xapian::Document& document);
     void add_values(Xapian::docid did,
-		    const map<Xapian::valueno, string>& values_);
+		    const std::map<Xapian::valueno, string>& values_);
 
     void make_posting(InMemoryDoc * doc,
-		      const string & tname,
+		      const std::string & tname,
 		      Xapian::docid did,
 		      Xapian::termpos position,
 		      Xapian::termcount wdf,
@@ -339,16 +339,16 @@
     Xapian::termcount get_doclength(Xapian::docid did) const;
     Xapian::termcount get_unique_terms(Xapian::docid did) const;
 
-    void get_freqs(const string & term,
+    void get_freqs(const std::string & term,
 		   Xapian::doccount * termfreq_ptr,
 		   Xapian::termcount * collfreq_ptr) const;
     Xapian::doccount get_value_freq(Xapian::valueno slot) const;
     std::string get_value_lower_bound(Xapian::valueno slot) const;
     std::string get_value_upper_bound(Xapian::valueno slot) const;
-    bool term_exists(const string & tname) const;
+    bool term_exists(const std::string & tname) const;
     bool has_positions() const;
 
-    LeafPostList * open_post_list(const string & tname) const;
+    LeafPostList * open_post_list(const std::string & tname) const;
     TermList * open_term_list(Xapian::docid did) const;
     Xapian::Document::Internal* open_document(Xapian::docid did,
 					      bool lazy) const;
@@ -358,10 +358,10 @@
     void set_metadata(const std::string & key, const std::string & value);
 
     Xapian::termcount positionlist_count(Xapian::docid did,
-					 const string & tname) const;
+					 const std::string & tname) const;
     PositionList * open_position_list(Xapian::docid did,
-				      const string & tname) const;
-    TermList * open_allterms(const string & prefix) const;
+				      const std::string & tname) const;
+    TermList * open_allterms(const std::string & prefix) const;
 
     XAPIAN_NORETURN(static void throw_database_closed());
 
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_document.cc xapian-core-1.4.21/backends/inmemory/inmemory_document.cc
--- xapian-core-1.4.21/backends/inmemory/inmemory_document.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_document.cc	2022-11-08 16:44:15.332462027 +0100
@@ -34,8 +34,8 @@
     db = static_cast<const InMemoryDatabase*>(database.get());
     if (rare(did > db->valuelists.size()))
 	RETURN(string());
-    map<Xapian::valueno, string> values_ = db->valuelists[did - 1];
-    map<Xapian::valueno, string>::const_iterator i;
+    std::map<Xapian::valueno, string> values_ = db->valuelists[did - 1];
+    std::map<Xapian::valueno, string>::const_iterator i;
     i = values_.find(slot);
     if (i == values_.end())
 	RETURN(string());
@@ -43,7 +43,7 @@
 }
 
 void
-InMemoryDocument::do_get_all_values(map<Xapian::valueno, string> &values_) const
+InMemoryDocument::do_get_all_values(std::map<Xapian::valueno, string> &values_) const
 {
     LOGCALL_VOID(DB, "InMemoryDocument::do_get_all_values", values_);
     const InMemoryDatabase * db;
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_document.h xapian-core-1.4.21/backends/inmemory/inmemory_document.h
--- xapian-core-1.4.21/backends/inmemory/inmemory_document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_document.h	2022-11-08 16:44:00.904513317 +0100
@@ -41,9 +41,9 @@
 
   public:
     /** Implementation of virtual methods @{ */
-    string do_get_value(Xapian::valueno slot) const;
-    void do_get_all_values(map<Xapian::valueno, string> & values_) const;
-    string do_get_data() const;
+    std::string do_get_value(Xapian::valueno slot) const;
+    void do_get_all_values(std::map<Xapian::valueno, string> & values_) const;
+    std::string do_get_data() const;
     /** @} */
 };
 
diff -ur xapian-core-1.4.21/backends/inmemory/inmemory_positionlist.h xapian-core-1.4.21/backends/inmemory/inmemory_positionlist.h
--- xapian-core-1.4.21/backends/inmemory/inmemory_positionlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/inmemory/inmemory_positionlist.h	2022-11-08 16:44:00.904513317 +0100
@@ -30,17 +30,17 @@
 #include "backends/positionlist.h"
 #include "api/documentterm.h"
 
-using namespace std;
+using std::string;
 
 /** A position list in a inmemory database. */
 class InMemoryPositionList : public PositionList
 {
     private:
 	/// The list of positions.
-	vector<Xapian::termpos> positions;
+	std::vector<Xapian::termpos> positions;
 
 	/// Position of iteration through positions
-	vector<Xapian::termpos>::const_iterator mypos;
+	std::vector<Xapian::termpos>::const_iterator mypos;
 
 	/// True if we have started iterating
 	bool iterating_in_progress;
diff -ur xapian-core-1.4.21/backends/multi/multi_alltermslist.cc xapian-core-1.4.21/backends/multi/multi_alltermslist.cc
--- xapian-core-1.4.21/backends/multi/multi_alltermslist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/multi/multi_alltermslist.cc	2022-11-08 16:44:15.336462012 +0100
@@ -43,8 +43,8 @@
     void operator()(CLASS *p) const { delete p; }
 };
 
-MultiAllTermsList::MultiAllTermsList(const vector<intrusive_ptr<Xapian::Database::Internal> > & dbs,
-				     const string & prefix)
+MultiAllTermsList::MultiAllTermsList(const std::vector<intrusive_ptr<Xapian::Database::Internal> > & dbs,
+				     const std::string & prefix)
 {
     // The 0 and 1 cases should be handled by our caller.
     AssertRel(dbs.size(), >=, 2);
@@ -75,7 +75,7 @@
 MultiAllTermsList::get_termfreq() const
 {
     if (termlists.empty()) return 0;
-    vector<TermList *>::const_iterator i = termlists.begin();
+    std::vector<TermList *>::const_iterator i = termlists.begin();
     Xapian::doccount total_tf = (*i)->get_termfreq();
     while (++i != termlists.end()) {
 	if ((*i)->get_termname() == current_term)
@@ -138,7 +138,7 @@
     // Assume the skip is likely to be a long distance, and rebuild the heap
     // from scratch.  FIXME: It would be useful to profile this against an
     // approach more like that next() uses if this ever gets heavy use.
-    vector<TermList*>::iterator i = termlists.begin();
+    std::vector<TermList*>::iterator i = termlists.begin();
     while (i != termlists.end()) {
 	(*i)->skip_to(term);
 	if ((*i)->at_end()) {
diff -ur xapian-core-1.4.21/backends/multi/multi_termlist.cc xapian-core-1.4.21/backends/multi/multi_termlist.cc
--- xapian-core-1.4.21/backends/multi/multi_termlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/multi/multi_termlist.cc	2022-11-08 16:44:15.340461999 +0100
@@ -73,7 +73,7 @@
     return tl->next();
 }
 
-TermList * MultiTermList::skip_to(const string & term)
+TermList * MultiTermList::skip_to(const std::string & term)
 {
     return tl->skip_to(term);
 }
diff -ur xapian-core-1.4.21/backends/multi/multi_termlist.h xapian-core-1.4.21/backends/multi/multi_termlist.h
--- xapian-core-1.4.21/backends/multi/multi_termlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/multi/multi_termlist.h	2022-11-08 16:44:00.912513288 +0100
@@ -42,7 +42,7 @@
 	/// Collate weighting information for the current term.
 	void accumulate_stats(Xapian::Internal::ExpandStats & stats) const;
 
-	string get_termname() const;
+	std::string get_termname() const;
 	Xapian::termcount get_wdf() const; // Number of occurrences of term in current doc
 	Xapian::doccount get_termfreq() const;  // Number of docs indexed by term
 	TermList * next();
diff -ur xapian-core-1.4.21/backends/multi/multi_valuelist.cc xapian-core-1.4.21/backends/multi/multi_valuelist.cc
--- xapian-core-1.4.21/backends/multi/multi_valuelist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/multi/multi_valuelist.cc	2022-11-08 16:44:15.336462012 +0100
@@ -81,7 +81,7 @@
     void operator()(CLASS *p) const { delete p; }
 };
 
-MultiValueList::MultiValueList(const vector<intrusive_ptr<Xapian::Database::Internal> > & dbs,
+MultiValueList::MultiValueList(const std::vector<intrusive_ptr<Xapian::Database::Internal> > & dbs,
 			       Xapian::valueno slot_)
     : current_docid(0), slot(slot_), multiplier(dbs.size())
 {
@@ -180,7 +180,7 @@
     // Assume the skip is likely to be a long distance, and rebuild the heap
     // from scratch.  FIXME: It would be useful to profile this against an
     // approach more like that next() uses if this ever gets heavy use.
-    vector<SubValueList*>::iterator i = valuelists.begin();
+    std::vector<SubValueList*>::iterator i = valuelists.begin();
     while (i != valuelists.end()) {
 	(*i)->skip_to(did, multiplier);
 	if ((*i)->at_end()) {
diff -ur xapian-core-1.4.21/backends/multivaluelist.h xapian-core-1.4.21/backends/multivaluelist.h
--- xapian-core-1.4.21/backends/multivaluelist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/multivaluelist.h	2022-11-08 16:44:00.912513288 +0100
@@ -104,7 +104,7 @@
      */
     bool check(Xapian::docid did);
 
-    /// Return a string description of this object.
+    /// Return a std::string description of this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/backends/prefix_compressed_strings.h xapian-core-1.4.21/backends/prefix_compressed_strings.h
--- xapian-core-1.4.21/backends/prefix_compressed_strings.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/prefix_compressed_strings.h	2022-11-08 16:44:00.912513288 +0100
@@ -116,7 +116,7 @@
 };
 
 struct PrefixCompressedStringItorGt {
-    /// Return true if and only if a's string is strictly greater than b's.
+    /// Return true if and only if a's std::string is strictly greater than b's.
     bool operator()(const PrefixCompressedStringItor *a,
 		    const PrefixCompressedStringItor *b) const {
 	return (**a > **b);
diff -ur xapian-core-1.4.21/backends/remote/net_postlist.cc xapian-core-1.4.21/backends/remote/net_postlist.cc
--- xapian-core-1.4.21/backends/remote/net_postlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/net_postlist.cc	2022-11-08 16:44:15.344461984 +0100
@@ -117,7 +117,7 @@
 string
 NetworkPostList::get_description() const
 {
-    string desc = "NetworkPostList(";
+    std::string desc = "NetworkPostList(";
     description_append(desc, term);
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/backends/remote/net_postlist.h xapian-core-1.4.21/backends/remote/net_postlist.h
--- xapian-core-1.4.21/backends/remote/net_postlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/net_postlist.h	2022-11-08 16:44:00.916513275 +0100
@@ -29,7 +29,7 @@
 #include "omassert.h"
 #include "remote-database.h"
 
-using namespace std;
+using std::string;
 
 /** A postlist in a remote database.
  */
@@ -38,7 +38,7 @@
 
     Xapian::Internal::intrusive_ptr<const RemoteDatabase> db;
 
-    string postings;
+    std::string postings;
     bool started;
     const char * pos;
     const char * pos_end;
@@ -49,7 +49,7 @@
     Xapian::doccount termfreq;
 
     /// Append a posting to the end of the postlist.
-    void append_posting(const string & serialised) {
+    void append_posting(const std::string & serialised) {
 	Assert(pos == NULL);
 	Assert(!started);
 	postings.append(serialised);
@@ -58,7 +58,7 @@
   public:
     /// Constructor.
     NetworkPostList(Xapian::Internal::intrusive_ptr<const RemoteDatabase> db_,
-		    const string & term_)
+		    const std::string & term_)
 	: LeafPostList(term_),
 	  db(db_), started(false), pos(NULL), pos_end(NULL),
 	  lastdocid(0), lastwdf(0), termfreq(0)
@@ -99,7 +99,7 @@
     Xapian::termcount get_wdf_upper_bound() const;
 
     /// Get a description of the postlist.
-    string get_description() const;
+    std::string get_description() const;
 };
 
 #endif /* XAPIAN_INCLUDED_NET_POSTLIST_H */
diff -ur xapian-core-1.4.21/backends/remote/net_termlist.cc xapian-core-1.4.21/backends/remote/net_termlist.cc
--- xapian-core-1.4.21/backends/remote/net_termlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/net_termlist.cc	2022-11-08 16:44:15.344461984 +0100
@@ -99,7 +99,7 @@
 }
 
 TermList *
-NetworkTermList::skip_to(const string & term)
+NetworkTermList::skip_to(const std::string & term)
 {
     while (current_position != items.end() && current_position->tname < term) {
 	++current_position;
diff -ur xapian-core-1.4.21/backends/remote/net_termlist.h xapian-core-1.4.21/backends/remote/net_termlist.h
--- xapian-core-1.4.21/backends/remote/net_termlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/net_termlist.h	2022-11-08 16:44:00.916513275 +0100
@@ -31,7 +31,7 @@
 #include "expand/expandweight.h"
 #include "remote-database.h"
 
-using namespace std;
+using std::string;
 
 /** An item in a NetworkTermList.
  */
@@ -39,7 +39,7 @@
     public:
 	/** The "name" of this term.
 	 */
-	string tname;
+	std::string tname;
 
 	/** The term frequency.
 	 *  This is the number of documents (in the network database)
@@ -64,11 +64,11 @@
     private:
 	/** The list of items comprising the termlist.
 	 */
-	vector<NetworkTermListItem> items;
+	std::vector<NetworkTermListItem> items;
 
 	/** The current position in the list.
 	 */
-	vector<NetworkTermListItem>::const_iterator current_position;
+	std::vector<NetworkTermListItem>::const_iterator current_position;
 
 	/** Whether we have yet started iterating through the list.
 	 */
@@ -114,7 +114,7 @@
 
 	// Collate weighting information for the current term.
 	void accumulate_stats(Xapian::Internal::ExpandStats &stats) const;
-	string get_termname() const;
+	std::string get_termname() const;
 	Xapian::termcount get_wdf() const;
 	Xapian::doccount get_termfreq() const;
 	TermList * next();
diff -ur xapian-core-1.4.21/backends/remote/remote-database.cc xapian-core-1.4.21/backends/remote/remote-database.cc
--- xapian-core-1.4.21/backends/remote/remote-database.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/remote-database.cc	2022-11-08 16:44:15.344461984 +0100
@@ -67,9 +67,9 @@
 	   (msg_code == MSG_TERMLIST && reply_code == REPLY_DOCLENGTH);
 }
 
-XAPIAN_NORETURN(static void throw_handshake_failed(const string & context));
+XAPIAN_NORETURN(static void throw_handshake_failed(const std::string & context));
 static void
-throw_handshake_failed(const string & context)
+throw_handshake_failed(const std::string & context)
 {
     throw Xapian::NetworkError("Handshake failed - is this a Xapian server?",
 			       context);
@@ -83,7 +83,7 @@
 }
 
 RemoteDatabase::RemoteDatabase(int fd, double timeout_,
-			       const string & context_, bool writable,
+			       const std::string & context_, bool writable,
 			       int flags)
 	: link(fd, fd, context_),
 	  context(context_),
@@ -113,7 +113,7 @@
 
     if (writable) {
 	if (flags & Xapian::DB_RETRY_LOCK) {
-	    const string & body = encode_length(flags & Xapian::DB_RETRY_LOCK);
+	    const std::string & body = encode_length(flags & Xapian::DB_RETRY_LOCK);
 	    update_stats(MSG_WRITEACCESS, body);
 	} else {
 	    update_stats(MSG_WRITEACCESS);
@@ -125,7 +125,7 @@
 RemoteDatabase::keep_alive()
 {
     send_message(MSG_KEEPALIVE, string());
-    string message;
+    std::string message;
     get_message(message, REPLY_DONE);
 }
 
@@ -137,14 +137,14 @@
 
     send_message(MSG_METADATAKEYLIST, prefix);
 
-    string message;
+    std::string message;
     AutoPtr<NetworkTermList> tlist(
 	new NetworkTermList(0, doccount,
 			    intrusive_ptr<const RemoteDatabase>(this),
 			    0));
-    vector<NetworkTermListItem> & items = tlist->items;
+    std::vector<NetworkTermListItem> & items = tlist->items;
 
-    string term = prefix;
+    std::string term = prefix;
     while (get_message_or_done(message, REPLY_METADATAKEYLIST)) {
 	NetworkTermListItem item;
 	term.resize(size_t(static_cast<unsigned char>(message[0])));
@@ -167,7 +167,7 @@
 
     send_message(MSG_TERMLIST, encode_length(did));
 
-    string message;
+    std::string message;
     get_message(message, REPLY_DOCLENGTH);
     const char * p = message.c_str();
     const char * p_end = p + message.size();
@@ -181,9 +181,9 @@
 	new NetworkTermList(doclen, doccount,
 			    intrusive_ptr<const RemoteDatabase>(this),
 			    did));
-    vector<NetworkTermListItem> & items = tlist->items;
+    std::vector<NetworkTermListItem> & items = tlist->items;
 
-    string term;
+    std::string term;
     while (get_message_or_done(message, REPLY_TERMLIST)) {
 	NetworkTermListItem item;
 	p = message.data();
@@ -201,7 +201,7 @@
 }
 
 TermList *
-RemoteDatabase::open_allterms(const string & prefix) const {
+RemoteDatabase::open_allterms(const std::string & prefix) const {
     // Ensure that total_length and doccount are up-to-date.
     if (!cached_stats_valid) update_stats();
 
@@ -211,10 +211,10 @@
 	new NetworkTermList(0, doccount,
 			    intrusive_ptr<const RemoteDatabase>(this),
 			    0));
-    vector<NetworkTermListItem> & items = tlist->items;
+    std::vector<NetworkTermListItem> & items = tlist->items;
 
-    string term = prefix;
-    string message;
+    std::string term = prefix;
+    std::string message;
     while (get_message_or_done(message, REPLY_ALLTERMS)) {
 	NetworkTermListItem item;
 	const char * p = message.data();
@@ -231,17 +231,17 @@
 }
 
 LeafPostList *
-RemoteDatabase::open_post_list(const string &term) const
+RemoteDatabase::open_post_list(const std::string &term) const
 {
     return new NetworkPostList(intrusive_ptr<const RemoteDatabase>(this), term);
 }
 
 Xapian::doccount
-RemoteDatabase::read_post_list(const string &term, NetworkPostList & pl) const
+RemoteDatabase::read_post_list(const std::string &term, NetworkPostList & pl) const
 {
     send_message(MSG_POSTLIST, term);
 
-    string message;
+    std::string message;
     get_message(message, REPLY_POSTLISTSTART);
 
     const char * p = message.data();
@@ -257,13 +257,13 @@
 }
 
 PositionList *
-RemoteDatabase::open_position_list(Xapian::docid did, const string &term) const
+RemoteDatabase::open_position_list(Xapian::docid did, const std::string &term) const
 {
     send_message(MSG_POSITIONLIST, encode_length(did) + term);
 
-    vector<Xapian::termpos> positions;
+    std::vector<Xapian::termpos> positions;
 
-    string message;
+    std::string message;
     Xapian::termpos lastpos = static_cast<Xapian::termpos>(-1);
     while (get_message_or_done(message, REPLY_POSITIONLIST)) {
 	const char * p = message.data();
@@ -325,11 +325,11 @@
     Assert(did);
 
     send_message(MSG_DOCUMENT, encode_length(did));
-    string doc_data;
-    map<Xapian::valueno, string> values;
+    std::string doc_data;
+    std::map<Xapian::valueno, string> values;
     get_message(doc_data, REPLY_DOCDATA);
 
-    string message;
+    std::string message;
     while (get_message_or_done(message, REPLY_VALUE)) {
 	const char * p = message.data();
 	const char * p_end = p + message.size();
@@ -342,14 +342,14 @@
 }
 
 bool
-RemoteDatabase::update_stats(message_type msg_code, const string & body) const
+RemoteDatabase::update_stats(message_type msg_code, const std::string & body) const
 {
     // MSG_MAX signals that we're handling the opening greeting, which isn't in
     // response to an explicit message.
     if (msg_code != MSG_MAX)
 	send_message(msg_code, body);
 
-    string message;
+    std::string message;
     if (!get_message_or_done(message, REPLY_UPDATE)) {
 	// The database was already open at the latest revision.
 	return false;
@@ -367,7 +367,7 @@
     int protocol_minor = static_cast<unsigned char>(*p++);
     if (protocol_major != XAPIAN_REMOTE_PROTOCOL_MAJOR_VERSION ||
 	protocol_minor < XAPIAN_REMOTE_PROTOCOL_MINOR_VERSION) {
-	string errmsg("Server supports protocol version");
+	std::string errmsg("Server supports protocol version");
 	if (protocol_minor) {
 	    errmsg += "s ";
 	    errmsg += str(protocol_major);
@@ -424,11 +424,11 @@
 }
 
 bool
-RemoteDatabase::term_exists(const string & tname) const
+RemoteDatabase::term_exists(const std::string & tname) const
 {
     Assert(!tname.empty());
     send_message(MSG_TERMEXISTS, tname);
-    string message;
+    std::string message;
     reply_type type = get_message(message,
 				  REPLY_TERMEXISTS,
 				  REPLY_TERMDOESNTEXIST);
@@ -436,12 +436,12 @@
 }
 
 void
-RemoteDatabase::get_freqs(const string & term,
+RemoteDatabase::get_freqs(const std::string & term,
 			  Xapian::doccount * termfreq_ptr,
 			  Xapian::termcount * collfreq_ptr) const
 {
     Assert(!term.empty());
-    string message;
+    std::string message;
     const char * p;
     const char * p_end;
     if (termfreq_ptr) {
@@ -471,7 +471,7 @@
 {
     if (mru_slot != slot) {
 	send_message(MSG_VALUESTATS, encode_length(slot));
-	string message;
+	std::string message;
 	get_message(message, REPLY_VALUESTATS);
 	const char * p = message.data();
 	const char * p_end = p + message.size();
@@ -524,7 +524,7 @@
 }
 
 Xapian::termcount
-RemoteDatabase::get_wdf_upper_bound(const string &) const
+RemoteDatabase::get_wdf_upper_bound(const std::string &) const
 {
     // The default implementation returns get_collection_freq(), but we
     // don't want the overhead of a remote message and reply per query
@@ -538,7 +538,7 @@
 {
     Assert(did != 0);
     send_message(MSG_DOCLENGTH, encode_length(did));
-    string message;
+    std::string message;
     get_message(message, REPLY_DOCLENGTH);
     const char * p = message.c_str();
     const char * p_end = p + message.size();
@@ -555,7 +555,7 @@
 {
     Assert(did != 0);
     send_message(MSG_UNIQUETERMS, encode_length(did));
-    string message;
+    std::string message;
     get_message(message, REPLY_UNIQUETERMS);
     const char * p = message.c_str();
     const char * p_end = p + message.size();
@@ -582,7 +582,7 @@
     if (rare(type) >= REPLY_MAX) {
 	if (required_type == REPLY_UPDATE)
 	    throw_handshake_failed(context);
-	string errmsg("Invalid reply type ");
+	std::string errmsg("Invalid reply type ");
 	errmsg += str(type);
 	throw Xapian::NetworkError(errmsg);
     }
@@ -590,7 +590,7 @@
 	unserialise_error(result, "REMOTE:", context);
     }
     if (type != required_type && type != required_type2) {
-	string errmsg("Expecting reply type ");
+	std::string errmsg("Expecting reply type ");
 	errmsg += str(int(required_type));
 	if (required_type2 != required_type) {
 	    errmsg += " or ";
@@ -605,11 +605,11 @@
 }
 
 void
-RemoteDatabase::send_message(message_type type, const string &message) const
+RemoteDatabase::send_message(message_type type, const std::string &message) const
 {
     double end_time = RealTime::end_time(timeout);
     while (pending_reply >= 0) {
-	string dummy;
+	std::string dummy;
 	int reply_code = link.get_message(dummy, end_time);
 	if (reply_code < 0)
 	    throw_connection_closed_unexpectedly();
@@ -673,10 +673,10 @@
 			  int percent_cutoff, double weight_cutoff,
 			  const Xapian::Weight *wtscheme,
 			  const Xapian::RSet &omrset,
-			  const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies)
+			  const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies)
 {
-    string tmp = query.serialise();
-    string message = encode_length(tmp.size());
+    std::string tmp = query.serialise();
+    std::string message = encode_length(tmp.size());
     message += tmp;
 
     // Serialise assorted Enquire settings.
@@ -724,7 +724,7 @@
 {
     if (nowait && !link.ready_to_read()) return false;
 
-    string message;
+    std::string message;
     get_message(message, REPLY_STATS);
     const char* p = message.data();
     unserialise_stats(p, p + message.size(), out);
@@ -738,7 +738,7 @@
 				  Xapian::doccount check_at_least,
 				  const Xapian::Weight::Internal &stats)
 {
-    string message = encode_length(first);
+    std::string message = encode_length(first);
     message += encode_length(maxitems);
     message += encode_length(check_at_least);
     message += serialise_stats(stats);
@@ -747,9 +747,9 @@
 
 void
 RemoteDatabase::get_mset(Xapian::MSet &mset,
-			 const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies)
+			 const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies)
 {
-    string message;
+    std::string message;
     get_message(message, REPLY_RESULTS);
     const char * p = message.data();
     const char * p_end = p + message.size();
@@ -759,7 +759,7 @@
 	    throw Xapian::NetworkError("Expected serialised matchspy");
 	size_t len;
 	decode_length_and_check(&p, p_end, len);
-	string spyresults(p, len);
+	std::string spyresults(p, len);
 	p += len;
 	i->merge_results(spyresults);
     }
@@ -774,7 +774,7 @@
     send_message(MSG_COMMIT, string());
 
     // We need to wait for a response to ensure documents have been committed.
-    string message;
+    std::string message;
     get_message(message, REPLY_DONE);
 
     uncommitted_changes = false;
@@ -789,7 +789,7 @@
     mru_slot = Xapian::BAD_VALUENO;
 
     send_message(MSG_CANCEL, string());
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 
     uncommitted_changes = false;
@@ -804,7 +804,7 @@
 
     send_message(MSG_ADDDOCUMENT, serialise_document(doc));
 
-    string message;
+    std::string message;
     get_message(message, REPLY_ADDDOCUMENT);
 
     const char * p = message.data();
@@ -822,7 +822,7 @@
     uncommitted_changes = true;
 
     send_message(MSG_DELETEDOCUMENT, encode_length(did));
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 }
 
@@ -834,7 +834,7 @@
     uncommitted_changes = true;
 
     send_message(MSG_DELETEDOCUMENTTERM, unique_term);
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 }
 
@@ -846,11 +846,11 @@
     mru_slot = Xapian::BAD_VALUENO;
     uncommitted_changes = true;
 
-    string message = encode_length(did);
+    std::string message = encode_length(did);
     message += serialise_document(doc);
 
     send_message(MSG_REPLACEDOCUMENT, message);
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 }
 
@@ -862,7 +862,7 @@
     mru_slot = Xapian::BAD_VALUENO;
     uncommitted_changes = true;
 
-    string message = encode_length(unique_term.size());
+    std::string message = encode_length(unique_term.size());
     message += unique_term;
     message += serialise_document(doc);
 
@@ -884,47 +884,47 @@
 }
 
 string
-RemoteDatabase::get_metadata(const string & key) const
+RemoteDatabase::get_metadata(const std::string & key) const
 {
     send_message(MSG_GETMETADATA, key);
-    string metadata;
+    std::string metadata;
     get_message(metadata, REPLY_METADATA);
     return metadata;
 }
 
 void
-RemoteDatabase::set_metadata(const string & key, const string & value)
+RemoteDatabase::set_metadata(const std::string & key, const std::string & value)
 {
     uncommitted_changes = true;
 
-    string data = encode_length(key.size());
+    std::string data = encode_length(key.size());
     data += key;
     data += value;
     send_message(MSG_SETMETADATA, data);
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 }
 
 void
-RemoteDatabase::add_spelling(const string & word,
+RemoteDatabase::add_spelling(const std::string & word,
 			     Xapian::termcount freqinc) const
 {
     uncommitted_changes = true;
 
-    string data = encode_length(freqinc);
+    std::string data = encode_length(freqinc);
     data += word;
     send_message(MSG_ADDSPELLING, data);
-    string dummy;
+    std::string dummy;
     get_message(dummy, REPLY_DONE);
 }
 
 void
-RemoteDatabase::remove_spelling(const string & word,
+RemoteDatabase::remove_spelling(const std::string & word,
 				Xapian::termcount freqdec) const
 {
     uncommitted_changes = true;
 
-    string data = encode_length(freqdec);
+    std::string data = encode_length(freqdec);
     data += word;
     send_message(MSG_REMOVESPELLING, data);
 }
diff -ur xapian-core-1.4.21/backends/remote/remote-database.h xapian-core-1.4.21/backends/remote/remote-database.h
--- xapian-core-1.4.21/backends/remote/remote-database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/remote-database.h	2022-11-08 16:44:00.916513275 +0100
@@ -87,10 +87,10 @@
     mutable int pending_reply = -1;
 
     /// The UUID of the remote database.
-    mutable string uuid;
+    mutable std::string uuid;
 
     /// The context to return with any error messages
-    string context;
+    std::string context;
 
     mutable bool cached_stats_valid;
 
@@ -129,7 +129,7 @@
      *	@param writable	Is this a WritableDatabase?
      *	@param flags	Xapian::DB_RETRY_LOCK or 0.
      */
-    RemoteDatabase(int fd, double timeout_, const string & context_,
+    RemoteDatabase(int fd, double timeout_, const std::string & context_,
 		   bool writable, int flags);
 
     /// Receive a message from the server.
@@ -148,12 +148,12 @@
     }
 
     /// Send a message to the server.
-    void send_message(message_type type, const string & data) const;
+    void send_message(message_type type, const std::string & data) const;
 
     /// Close the socket
     void do_close();
 
-    bool get_posting(Xapian::docid &did, double &w, string &value);
+    bool get_posting(Xapian::docid &did, double &w, std::string &value);
 
     /// The timeout value used in network communications, in seconds.
     double timeout;
@@ -194,7 +194,7 @@
 		   int percent_cutoff, double weight_cutoff,
 		   const Xapian::Weight *wtscheme,
 		   const Xapian::RSet &omrset,
-		   const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
+		   const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
 
     /** Get the stats from the remote server.
      *
@@ -210,7 +210,7 @@
 
     /// Get the MSet from the remote server.
     void get_mset(Xapian::MSet &mset,
-		  const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
+		  const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
 
     /// Get remote metadata key list.
     TermList * open_metadata_keylist(const std::string & prefix) const;
@@ -219,7 +219,7 @@
     TermList * open_term_list(Xapian::docid did) const;
 
     /// Iterate all terms.
-    TermList * open_allterms(const string & prefix) const;
+    TermList * open_allterms(const std::string & prefix) const;
 
     bool has_positions() const;
 
@@ -227,12 +227,12 @@
 
     void close();
 
-    LeafPostList * open_post_list(const string & tname) const;
+    LeafPostList * open_post_list(const std::string & tname) const;
 
-    Xapian::doccount read_post_list(const string &term, NetworkPostList & pl) const;
+    Xapian::doccount read_post_list(const std::string &term, NetworkPostList & pl) const;
 
     PositionList * open_position_list(Xapian::docid did,
-				      const string & tname) const;
+				      const std::string & tname) const;
 
     /// Get a remote document.
     Xapian::Document::Internal * open_document(Xapian::docid did, bool lazy) const;
@@ -249,9 +249,9 @@
     Xapian::termcount get_unique_terms(Xapian::docid did) const;
 
     /// Check if term exists.
-    bool term_exists(const string & tname) const;
+    bool term_exists(const std::string & tname) const;
 
-    void get_freqs(const string & term,
+    void get_freqs(const std::string & term,
 		   Xapian::doccount * termfreq_ptr,
 		   Xapian::termcount * collfreq_ptr) const;
 
@@ -263,7 +263,7 @@
 
     Xapian::termcount get_doclength_lower_bound() const;
     Xapian::termcount get_doclength_upper_bound() const;
-    Xapian::termcount get_wdf_upper_bound(const string & term) const;
+    Xapian::termcount get_wdf_upper_bound(const std::string & term) const;
 
     void commit();
 
@@ -280,9 +280,9 @@
 
     std::string get_uuid() const;
 
-    string get_metadata(const string & key) const;
+    std::string get_metadata(const std::string & key) const;
 
-    void set_metadata(const string & key, const string & value);
+    void set_metadata(const std::string & key, const std::string & value);
 
     void add_spelling(const std::string&, Xapian::termcount) const;
 
diff -ur xapian-core-1.4.21/backends/remote/remote-document.cc xapian-core-1.4.21/backends/remote/remote-document.cc
--- xapian-core-1.4.21/backends/remote/remote-document.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/remote-document.cc	2022-11-08 16:44:15.340461999 +0100
@@ -35,7 +35,7 @@
 }
 
 void
-RemoteDocument::do_get_all_values(map<Xapian::valueno, string> &) const
+RemoteDocument::do_get_all_values(std::map<Xapian::valueno, string> &) const
 {
     LOGCALL_VOID(DB, "RemoteDocument::do_get_all_values", Literal("[&values_]"));
     // Our ctor sets the values, so we should never get here.
diff -ur xapian-core-1.4.21/backends/remote/remote-document.h xapian-core-1.4.21/backends/remote/remote-document.h
--- xapian-core-1.4.21/backends/remote/remote-document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/remote/remote-document.h	2022-11-08 16:44:00.916513275 +0100
@@ -41,8 +41,8 @@
      *			may be modified by the call.
      */
     RemoteDocument(const Xapian::Database::Internal *db, Xapian::docid did_,
-		   const string & data_,
-		   map<Xapian::valueno, string> &values_)
+		   const std::string & data_,
+		   std::map<Xapian::valueno, string> &values_)
 	: Xapian::Document::Internal(db, did_)
     {
 	set_data(data_);
@@ -51,9 +51,9 @@
 
   public:
     /** Implementation of virtual methods @{ */
-    string do_get_value(Xapian::valueno slot) const;
-    void do_get_all_values(map<Xapian::valueno, string> & values_) const;
-    string do_get_data() const;
+    std::string do_get_value(Xapian::valueno slot) const;
+    void do_get_all_values(std::map<Xapian::valueno, string> & values_) const;
+    std::string do_get_data() const;
     /** @} */
 };
 
diff -ur xapian-core-1.4.21/backends/slowvaluelist.cc xapian-core-1.4.21/backends/slowvaluelist.cc
--- xapian-core-1.4.21/backends/slowvaluelist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/slowvaluelist.cc	2022-11-08 16:44:15.340461999 +0100
@@ -71,7 +71,7 @@
 		continue;
 	    AutoPtr<Xapian::Document::Internal>
 		doc(static_cast<Xapian::Document::Internal*>(d));
-	    string value = doc->get_value(slot);
+	    std::string value = doc->get_value(slot);
 	    if (!value.empty()) {
 		swap(current_value, value);
 		return;
@@ -123,7 +123,7 @@
 string
 SlowValueList::get_description() const
 {
-    string desc = "SlowValueList(slot=";
+    std::string desc = "SlowValueList(slot=";
     desc += str(slot);
     if (last_docid != 0) {
 	desc += ", docid=";
diff -ur xapian-core-1.4.21/backends/uuids.cc xapian-core-1.4.21/backends/uuids.cc
--- xapian-core-1.4.21/backends/uuids.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/uuids.cc	2022-11-08 16:44:15.416461728 +0100
@@ -56,7 +56,7 @@
 
 using namespace std;
 
-/// Bit-mask to determine where to put hyphens in the string representation.
+/// Bit-mask to determine where to put hyphens in the std::string representation.
 static constexpr unsigned UUID_GAP_MASK = 0x2a8;
 
 void
@@ -119,7 +119,7 @@
 string
 Uuid::to_string() const
 {
-    string result;
+    std::string result;
     result.reserve(STRING_SIZE);
     for (unsigned i = 0; i != BINARY_SIZE; ++i) {
 	unsigned char ch = uuid_data[i];
diff -ur xapian-core-1.4.21/backends/uuids.h xapian-core-1.4.21/backends/uuids.h
--- xapian-core-1.4.21/backends/uuids.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/uuids.h	2022-11-08 16:44:00.940513189 +0100
@@ -30,7 +30,7 @@
     /// The size of a UUID in bytes.
     static constexpr unsigned BINARY_SIZE = 16;
 
-    /// The size of a UUID string in bytes (not including trailing '\0').
+    /// The size of a UUID std::string in bytes (not including trailing '\0').
     static constexpr unsigned STRING_SIZE = 36;
 
     Uuid() {}
diff -ur xapian-core-1.4.21/backends/valuelist.h xapian-core-1.4.21/backends/valuelist.h
--- xapian-core-1.4.21/backends/valuelist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/backends/valuelist.h	2022-11-08 16:44:00.944513174 +0100
@@ -92,7 +92,7 @@
      */
     virtual bool check(Xapian::docid did);
 
-    /// Return a string description of this object.
+    /// Return a std::string description of this object.
     virtual std::string get_description() const = 0;
 };
 
diff -ur xapian-core-1.4.21/bin/xapian-compact.cc xapian-core-1.4.21/bin/xapian-compact.cc
--- xapian-core-1.4.21/bin/xapian-compact.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-compact.cc	2022-11-08 16:44:15.564461202 +0100
@@ -67,16 +67,16 @@
 
     void set_quiet(bool quiet_) { quiet = quiet_; }
 
-    void set_status(const string & table, const string & status);
+    void set_status(const std::string & table, const std::string & status);
 
     string
-    resolve_duplicate_metadata(const string & key,
+    resolve_duplicate_metadata(const std::string & key,
 			       size_t n,
-			       const string tags[]);
+			       const std::string tags[]);
 };
 
 void
-MyCompactor::set_status(const string & table, const string & status)
+MyCompactor::set_status(const std::string & table, const std::string & status)
 {
     if (quiet)
 	return;
@@ -87,9 +87,9 @@
 }
 
 string
-MyCompactor::resolve_duplicate_metadata(const string & key,
+MyCompactor::resolve_duplicate_metadata(const std::string & key,
 					size_t n,
-					const string tags[])
+					const std::string tags[])
 {
     (void)key;
     while (--n) {
@@ -179,7 +179,7 @@
     }
 
     // Path to the database to create.
-    string destdir = argv[argc - 1];
+    std::string destdir = argv[argc - 1];
 
     try {
 	Xapian::Database src;
diff -ur xapian-core-1.4.21/bin/xapian-delve.cc xapian-core-1.4.21/bin/xapian-delve.cc
--- xapian-core-1.4.21/bin/xapian-delve.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-delve.cc	2022-11-08 16:44:15.564461202 +0100
@@ -160,7 +160,7 @@
 {
     switch (value_decode) {
 	case VALUE_ESCAPE: {
-	    string esc;
+	    std::string esc;
 	    description_append(esc, value);
 	    cout << esc;
 	    break;
@@ -196,8 +196,8 @@
 
 static void
 show_values(Database &db,
-	    vector<docid>::const_iterator i,
-	    vector<docid>::const_iterator end)
+	    std::vector<docid>::const_iterator i,
+	    std::vector<docid>::const_iterator end)
 {
     while (i != end) {
 	cout << "Values for record #" << *i << ':';
@@ -209,8 +209,8 @@
 
 static void
 show_value(Database &db,
-	   vector<docid>::const_iterator i,
-	   vector<docid>::const_iterator end,
+	   std::vector<docid>::const_iterator i,
+	   std::vector<docid>::const_iterator end,
 	   Xapian::valueno slot)
 {
     while (i != end) {
@@ -230,8 +230,8 @@
 
 static void
 show_docdata(Database &db,
-	     vector<docid>::const_iterator i,
-	     vector<docid>::const_iterator end)
+	     std::vector<docid>::const_iterator i,
+	     std::vector<docid>::const_iterator end)
 {
     while (i != end) {
 	cout << "Data for record #" << *i << ':' << endl;
@@ -268,7 +268,7 @@
     cout << ':';
 
     while (t != tend) {
-	const string & term = *t;
+	const std::string & term = *t;
 	cout << separator << term;
 	if (verbose) {
 	    if (did != 0)
@@ -286,8 +286,8 @@
 
 static void
 show_termlists(Database &db,
-	       vector<docid>::const_iterator i,
-	       vector<docid>::const_iterator end)
+	       std::vector<docid>::const_iterator i,
+	       std::vector<docid>::const_iterator end)
 {
     // Display termlists
     while (i != end) {
@@ -311,9 +311,9 @@
     }
 
     const char * all_terms = NULL;
-    vector<docid> recnos;
-    vector<string> terms;
-    vector<string> dbs;
+    std::vector<docid> recnos;
+    std::vector<string> terms;
+    std::vector<string> dbs;
     Stem stemmer;
 
     valueno slot = 0; // Avoid "may be used uninitialised" warnings.
@@ -474,9 +474,9 @@
 	return 0;
     }
 
-    vector<string>::const_iterator i;
+    std::vector<string>::const_iterator i;
     for (i = terms.begin(); i != terms.end(); ++i) {
-	string term = stemmer(*i);
+	std::string term = stemmer(*i);
 	PostingIterator p = db.postlist_begin(term);
 	PostingIterator pend = db.postlist_end(term);
 	if (p == pend) {
@@ -501,7 +501,7 @@
 	    cout << endl;
 	} else {
 	    // Display position lists
-	    vector<docid>::const_iterator j;
+	    std::vector<docid>::const_iterator j;
 	    for (j = recnos.begin(); j != recnos.end(); ++j) {
 		p.skip_to(*j);
 		if (p == pend || *p != *j) {
diff -ur xapian-core-1.4.21/bin/xapian-inspect.cc xapian-core-1.4.21/bin/xapian-inspect.cc
--- xapian-core-1.4.21/bin/xapian-inspect.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-inspect.cc	2022-11-08 16:44:15.564461202 +0100
@@ -84,7 +84,7 @@
     auto bslash = s.find('\\');
     if (bslash == string::npos)
 	return s;
-    string r(s, 0, bslash);
+    std::string r(s, 0, bslash);
     for (auto i = s.begin() + bslash; i != s.end(); ++i) {
 	char ch = *i;
 	if (ch == '\\') {
@@ -224,7 +224,7 @@
 	{NULL,		0, 0, 0}
     };
 
-    string table_name;
+    std::string table_name;
 
     int c;
     while ((c = gnu_getopt_long(argc, argv, "t:", long_opts, 0)) != -1) {
@@ -251,7 +251,7 @@
     }
 
     // Path to the DB to inspect (possibly with a table name appended).
-    string db_path(argv[optind]);
+    std::string db_path(argv[optind]);
     bool arg_is_directory = dir_exists(db_path);
     if (arg_is_directory && table_name.empty()) {
 	cerr << argv[0]
@@ -324,7 +324,7 @@
 
 	GlassTable* table_ptr;
 	if (single_file_fd < 0) {
-	    string table_path = db_path;
+	    std::string table_path = db_path;
 	    table_path += '/';
 	    table_path += table_name;
 	    table_path += '.';
@@ -351,7 +351,7 @@
 wait_for_input:
 	    cout << "? " << flush;
 
-	    string input;
+	    std::string input;
 	    getline(cin, input);
 	    if (cin.eof()) break;
 
diff -ur xapian-core-1.4.21/bin/xapian-progsrv.cc xapian-core-1.4.21/bin/xapian-progsrv.cc
--- xapian-core-1.4.21/bin/xapian-progsrv.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-progsrv.cc	2022-11-08 16:44:15.564461202 +0100
@@ -97,7 +97,7 @@
      * to open the database(s) to check they work - if they can't be opened the
      * client will get an exception right away anyway.
      */
-    vector<string> dbnames(argv + optind, argv + argc);
+    std::vector<string> dbnames(argv + optind, argv + argc);
 
     try {
 	// We communicate with the client via stdin (fd 0) and stdout (fd 1).
diff -ur xapian-core-1.4.21/bin/xapian-replicate.cc xapian-core-1.4.21/bin/xapian-replicate.cc
--- xapian-core-1.4.21/bin/xapian-replicate.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-replicate.cc	2022-11-08 16:44:15.560461217 +0100
@@ -89,9 +89,9 @@
 	{NULL,		0, 0, 0}
     };
 
-    string host;
+    std::string host;
     int port = 0;
-    string masterdb;
+    std::string masterdb;
     int interval = DEFAULT_INTERVAL;
     bool one_shot = false;
     enum { NORMAL, VERBOSE, QUIET } verbosity = NORMAL;
@@ -163,7 +163,7 @@
     }
 
     // Path to the database to create/update.
-    string dbpath(argv[optind]);
+    std::string dbpath(argv[optind]);
 
     if (masterdb.empty())
 	masterdb = dbpath;
diff -ur xapian-core-1.4.21/bin/xapian-replicate-server.cc xapian-core-1.4.21/bin/xapian-replicate-server.cc
--- xapian-core-1.4.21/bin/xapian-replicate-server.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-replicate-server.cc	2022-11-08 16:44:15.564461202 +0100
@@ -61,7 +61,7 @@
 	{NULL,		0, 0, 0}
     };
 
-    string host;
+    std::string host;
     int port = 0;
 
     bool one_shot = false;
@@ -97,7 +97,7 @@
     }
 
     // Path to the database to create/update.
-    string dbpath(argv[optind]);
+    std::string dbpath(argv[optind]);
 
     try {
 	ReplicateTcpServer server(host, port, dbpath);
diff -ur xapian-core-1.4.21/bin/xapian-tcpsrv.cc xapian-core-1.4.21/bin/xapian-tcpsrv.cc
--- xapian-core-1.4.21/bin/xapian-tcpsrv.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/bin/xapian-tcpsrv.cc	2022-11-08 16:44:15.560461217 +0100
@@ -87,7 +87,7 @@
 }
 
 int main(int argc, char **argv) {
-    string host;
+    std::string host;
     int port = 0;
     double active_timeout = MSECS_ACTIVE_TIMEOUT_DEFAULT * 1e-3;
     double idle_timeout   = MSECS_IDLE_TIMEOUT_DEFAULT * 1e-3;
diff -ur xapian-core-1.4.21/common/append_filename_arg.h xapian-core-1.4.21/common/append_filename_arg.h
--- xapian-core-1.4.21/common/append_filename_arg.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/append_filename_arg.h	2022-11-08 16:44:00.880513402 +0100
@@ -1,5 +1,5 @@
 /** @file
- *  @brief Append filename argument to a command string with suitable escaping
+ *  @brief Append filename argument to a command std::string with suitable escaping
  */
 /* Copyright (C) 2003,2004,2007,2012,2019 Olly Betts
  *
@@ -54,7 +54,7 @@
     cmd += '"';
 #else
     // Allow for the typical case of a filename without single quote characters
-    // in - this reserving is just an optimisation, and the string will grow
+    // in - this reserving is just an optimisation, and the std::string will grow
     // larger if necessary.
     cmd.reserve(cmd.size() + arg.size() + 5);
 
diff -ur xapian-core-1.4.21/common/bitstream.cc xapian-core-1.4.21/common/bitstream.cc
--- xapian-core-1.4.21/common/bitstream.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/bitstream.cc	2022-11-08 16:44:15.308462113 +0100
@@ -152,7 +152,7 @@
 }
 
 void
-BitWriter::encode_interpolative(const vector<Xapian::termpos>& pos, int j, int k)
+BitWriter::encode_interpolative(const std::vector<Xapian::termpos>& pos, int j, int k)
 {
     // "Interpolative code" - for an algorithm description, see "Managing
     // Gigabytes" - pages 126-127 in the second edition.  You can probably
diff -ur xapian-core-1.4.21/common/compression_stream.cc xapian-core-1.4.21/common/compression_stream.cc
--- xapian-core-1.4.21/common/compression_stream.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/compression_stream.cc	2022-11-08 16:44:15.316462084 +0100
@@ -98,7 +98,7 @@
 	int err = inflate(inflate_zstream, Z_SYNC_FLUSH);
 	if (err != Z_OK && err != Z_STREAM_END) {
 	    if (err == Z_MEM_ERROR) throw std::bad_alloc();
-	    string msg = "inflate failed";
+	    std::string msg = "inflate failed";
 	    if (inflate_zstream->msg) {
 		msg += " (";
 		msg += inflate_zstream->msg;
@@ -138,7 +138,7 @@
 	    deflate_zstream = 0;
 	    throw std::bad_alloc();
 	}
-	string msg = "deflateInit2 failed (";
+	std::string msg = "deflateInit2 failed (";
 	if (deflate_zstream->msg) {
 	    msg += deflate_zstream->msg;
 	} else {
@@ -174,7 +174,7 @@
 	    inflate_zstream = 0;
 	    throw std::bad_alloc();
 	}
-	string msg = "inflateInit2 failed (";
+	std::string msg = "inflateInit2 failed (";
 	if (inflate_zstream->msg) {
 	    msg += inflate_zstream->msg;
 	} else {
diff -ur xapian-core-1.4.21/common/debuglog.cc xapian-core-1.4.21/common/debuglog.cc
--- xapian-core-1.4.21/common/debuglog.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/debuglog.cc	2022-11-08 16:44:15.312462098 +0100
@@ -56,7 +56,7 @@
 	    // Filename "-" means "log to stderr".
 	    fd = 2;
 	} else {
-	    string fnm, pid;
+	    std::string fnm, pid;
 	    while (*f) {
 		if (*f == '%') {
 		    if (f[1] == 'p') {
@@ -124,7 +124,7 @@
     // which expects errno not to change.
     int saved_errno = errno;
 
-    string line;
+    std::string line;
     line.reserve(9 + indent_level + msg.size());
     line = char(category) + '@';
     line += ' ';
diff -ur xapian-core-1.4.21/common/errno_to_string.cc xapian-core-1.4.21/common/errno_to_string.cc
--- xapian-core-1.4.21/common/errno_to_string.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/errno_to_string.cc	2022-11-08 16:44:15.308462113 +0100
@@ -42,7 +42,7 @@
 void
 errno_to_string(int e, string& s)
 {
-    // Use a thread-safe way to convert an errno value to a string if possible.
+    // Use a thread-safe way to convert an errno value to a std::string if possible.
 #ifdef HAVE_STRERRORDESC_NP
     // GNU-specific replacement for sys_errlist and sys_nerr, added in glibc
     // 2.32.
@@ -95,7 +95,7 @@
     // actual longest on Linux in English is EILSEQ which needs 50 bytes.
     char buf[1024];
 # ifdef STRERROR_R_CHAR_P
-    // Returns char* pointing to string describing error.
+    // Returns char* pointing to std::string describing error.
     s += strerror_r(e, buf, sizeof(buf));
 # else
     // XSI-compliant strerror_r returns int:  0 means success; a positive error
diff -ur xapian-core-1.4.21/common/fileutils.cc xapian-core-1.4.21/common/fileutils.cc
--- xapian-core-1.4.21/common/fileutils.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/fileutils.cc	2022-11-08 16:44:15.304462126 +0100
@@ -47,7 +47,7 @@
 };
 
 void
-removedir(const string &dirname)
+removedir(const std::string &dirname)
 {
     DIR * dir;
 
@@ -67,7 +67,7 @@
 		    break;
 		throw Xapian::DatabaseError("Cannot read entry from directory at '" + dirname + "'", errno);
 	    }
-	    string name(entry->d_name);
+	    std::string name(entry->d_name);
 	    if (name == "." || name == "..")
 		continue;
 	    if (unlink((dirname + "/" + name).c_str())) {
@@ -83,14 +83,14 @@
 #ifdef __WIN32__
 /// Return true iff a path starts with a drive letter.
 static bool
-has_drive(const string &path)
+has_drive(const std::string &path)
 {
     return (path.size() >= 2 && path[1] == ':');
 }
 
 /// Return true iff path is a UNCW path.
 static bool
-uncw_path(const string & path)
+uncw_path(const std::string & path)
 {
     return (path.size() >= 4 && memcmp(path.data(), "\\\\?\\", 4) == 0);
 }
@@ -102,7 +102,7 @@
 #endif
 
 void
-resolve_relative_path(string & path, const string & base)
+resolve_relative_path(string & path, const std::string & base)
 {
 #ifndef __WIN32__
     if (path.empty() || path[0] != '/') {
diff -ur xapian-core-1.4.21/common/getopt.cc xapian-core-1.4.21/common/getopt.cc
--- xapian-core-1.4.21/common/getopt.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/getopt.cc	2022-11-08 16:44:15.304462126 +0100
@@ -297,7 +297,7 @@
    that is not an option.  (The ARGV-elements have been permuted
    so that those that are not options now come last.)
 
-   OPTSTRING is a string containing the legitimate option characters.
+   OPTSTRING is a std::string containing the legitimate option characters.
    If an option character is seen that is not listed in OPTSTRING,
    return '?' after printing an error message.  If you set `opterr' to
    zero, the error message is suppressed but we still return '?'.
diff -ur xapian-core-1.4.21/common/msvc_dirent.cc xapian-core-1.4.21/common/msvc_dirent.cc
--- xapian-core-1.4.21/common/msvc_dirent.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/msvc_dirent.cc	2022-11-08 16:44:15.308462113 +0100
@@ -45,7 +45,7 @@
     intptr_t            handle; /* -1 for failed rewind */
     struct _finddata_t  info;
     struct dirent       result; /* d_name null iff first time */
-    char                name[1];/* null-terminated char string */
+    char                name[1];/* null-terminated char std::string */
 };
 
 DIR *opendir(const char *name)
diff -ur xapian-core-1.4.21/common/pack.h xapian-core-1.4.21/common/pack.h
--- xapian-core-1.4.21/common/pack.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/pack.h	2022-11-08 16:44:00.872513430 +0100
@@ -50,7 +50,7 @@
 
 /** Append an encoded bool to a string.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The bool to encode.
  */
 inline void
@@ -80,12 +80,12 @@
     return true;
 }
 
-/** Append an encoded unsigned integer to a string as the last item.
+/** Append an encoded unsigned integer to a std::string as the last item.
  *
  *  This encoding is only suitable when this is the last thing encoded as
  *  the encoding used doesn't contain its own length.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The unsigned integer to encode.
  */
 template<class U>
@@ -134,14 +134,14 @@
  *
  *  [Chert variant]
  *
- *  The appended string data will sort in the same order as the unsigned
+ *  The appended std::string data will sort in the same order as the unsigned
  *  integer being encoded.
  *
  *  Note that the first byte of the encoding will never be \xff, so it is
  *  safe to store the result of this function immediately after the result of
  *  pack_string_preserving_sort().
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The unsigned integer to encode.
  */
 template<class U>
@@ -254,14 +254,14 @@
  *
  *  [Glass and newer variant]
  *
- *  The appended string data will sort in the same order as the unsigned
+ *  The appended std::string data will sort in the same order as the unsigned
  *  integer being encoded.
  *
  *  Note that the first byte of the encoding will never be \xff, so it is
  *  safe to store the result of this function immediately after the result of
  *  pack_string_preserving_sort().
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The unsigned integer to encode.
  */
 template<class U>
@@ -374,7 +374,7 @@
 
 /** Append an encoded unsigned integer to a string.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The unsigned integer to encode.
  */
 template<class U>
@@ -392,7 +392,7 @@
 
 /** Append an encoded unsigned integer (bool type) to a string.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The unsigned integer to encode.
  */
 template<>
@@ -470,7 +470,7 @@
 
 /** Append an encoded std::string to a string.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The std::string to encode.
  */
 inline void
@@ -480,10 +480,10 @@
     s += value;
 }
 
-/** Append an encoded C-style string to a string.
+/** Append an encoded C-style std::string to a string.
  *
- *  @param s		The string to append to.
- *  @param ptr		The C-style string to encode.
+ *  @param s		The std::string to append to.
+ *  @param ptr		The C-style std::string to encode.
  */
 inline void
 pack_string(std::string & s, const char * ptr)
@@ -526,10 +526,10 @@
  *  ensure this.  Note that pack_uint_preserving_sort() can never produce
  *  \xff as its first byte so is safe to use immediately afterwards.
  *
- *  @param s		The string to append to.
+ *  @param s		The std::string to append to.
  *  @param value	The std::string to encode.
  *  @param last		If true, this is the last thing to be encoded in this
- *			string - see note below (default: false)
+ *			std::string - see note below (default: false)
  *
  *  It doesn't make sense to use pack_string_preserving_sort() if nothing can
  *  ever follow, but if optional items can, you can set last=true in cases
diff -ur xapian-core-1.4.21/common/parseint.h xapian-core-1.4.21/common/parseint.h
--- xapian-core-1.4.21/common/parseint.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/parseint.h	2022-11-08 16:44:00.896513345 +0100
@@ -1,5 +1,5 @@
 /** @file
- * @brief Parse signed and unsigned type from string and check for trailing characters.
+ * @brief Parse signed and unsigned type from std::string and check for trailing characters.
  */
 /* Copyright (C) 2019 Olly Betts
  * Copyright (C) 2019 Vaibhav Kansagara
diff -ur xapian-core-1.4.21/common/replicate_utils.cc xapian-core-1.4.21/common/replicate_utils.cc
--- xapian-core-1.4.21/common/replicate_utils.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/replicate_utils.cc	2022-11-08 16:44:15.320462069 +0100
@@ -40,16 +40,16 @@
 using namespace std;
 
 int
-create_changeset_file(const string & changeset_dir,
-		      const string & filename,
-		      string & changes_name)
+create_changeset_file(const std::string & changeset_dir,
+		      const std::string & filename,
+		      std::string & changes_name)
 {
     changes_name = changeset_dir;
     changes_name += '/';
     changes_name += filename;
     int changes_fd = posixy_open(changes_name.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0666);
     if (changes_fd < 0) {
-	string message("Couldn't open changeset to write: ");
+	std::string message("Couldn't open changeset to write: ");
 	message += changes_name;
 	throw Xapian::DatabaseError(message, errno);
     }
@@ -57,7 +57,7 @@
 }
 
 void
-write_and_clear_changes(int changes_fd, string & buf, size_t bytes)
+write_and_clear_changes(int changes_fd, std::string & buf, size_t bytes)
 {
     if (changes_fd != -1) {
 	io_write(changes_fd, buf.data(), bytes);
diff -ur xapian-core-1.4.21/common/replicate_utils.h xapian-core-1.4.21/common/replicate_utils.h
--- xapian-core-1.4.21/common/replicate_utils.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/replicate_utils.h	2022-11-08 16:44:00.864513459 +0100
@@ -32,7 +32,7 @@
  *
  *  @param changeset_dir The directory for the changesets.
  *  @param filename The name of the changeset file.
- *  @param changes_name A string which will be set to the path of the changeset
+ *  @param changes_name A std::string which will be set to the path of the changeset
  *  file.
  *
  *  @return The open file descriptor.
diff -ur xapian-core-1.4.21/common/serialise-double.cc xapian-core-1.4.21/common/serialise-double.cc
--- xapian-core-1.4.21/common/serialise-double.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/serialise-double.cc	2022-11-08 16:44:15.312462098 +0100
@@ -100,7 +100,7 @@
 
     int exp = base256ify_double(v);
 
-    string result;
+    std::string result;
 
     if (exp <= 6 && exp >= -7) {
 	unsigned char b = static_cast<unsigned char>(exp + 7);
diff -ur xapian-core-1.4.21/common/stringutils.h xapian-core-1.4.21/common/stringutils.h
--- xapian-core-1.4.21/common/stringutils.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/common/stringutils.h	2022-11-08 16:44:00.876513417 +0100
@@ -32,13 +32,13 @@
  */
 #define STRINGIZE_(X) #X
 
-/// The STRINGIZE macro converts its parameter into a string constant.
+/// The STRINGIZE macro converts its parameter into a std::string constant.
 #define STRINGIZE(X) STRINGIZE_(X)
 
-/** Returns the length of a string constant.
+/** Returns the length of a std::string constant.
  *
- *  We rely on concatenation of string literals to produce an error if this
- *  macro is applied to something other than a string literal.
+ *  We rely on concatenation of std::string literals to produce an error if this
+ *  macro is applied to something other than a std::string literal.
  */
 #define CONST_STRLEN(S) (sizeof(S"") - 1)
 
diff -ur xapian-core-1.4.21/examples/copydatabase.cc xapian-core-1.4.21/examples/copydatabase.cc
--- xapian-core-1.4.21/examples/copydatabase.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/copydatabase.cc	2022-11-08 16:44:15.444461628 +0100
@@ -83,7 +83,7 @@
     Xapian::WritableDatabase db_out(dest, Xapian::DB_CREATE);
 
     for (int i = 1; i < argc - 1; ++i) {
-	string src = argv[i];
+	std::string src = argv[i];
 	if (!src.empty()) {
 	    // Remove any trailing directory separator.
 	    char ch = src.back();
@@ -150,7 +150,7 @@
 	cout << "Copying synonym data..." << flush;
 	Xapian::TermIterator synkey = db_in.synonym_keys_begin();
 	while (synkey != db_in.synonym_keys_end()) {
-	    string key = *synkey;
+	    std::string key = *synkey;
 	    Xapian::TermIterator syn = db_in.synonyms_begin(key);
 	    while (syn != db_in.synonyms_end(key)) {
 		db_out.add_synonym(key, *syn);
@@ -163,7 +163,7 @@
 	cout << "Copying user metadata..." << flush;
 	Xapian::TermIterator metakey = db_in.metadata_keys_begin();
 	while (metakey != db_in.metadata_keys_end()) {
-	    string key = *metakey;
+	    std::string key = *metakey;
 	    db_out.set_metadata(key, db_in.get_metadata(key));
 	    ++metakey;
 	}
diff -ur xapian-core-1.4.21/examples/quest.cc xapian-core-1.4.21/examples/quest.cc
--- xapian-core-1.4.21/examples/quest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/quest.cc	2022-11-08 16:44:15.444461628 +0100
@@ -49,7 +49,7 @@
     "was", "what", "when", "where", "which", "who", "why", "will", "with"
 };
 
-/** Common string to integer map entry for option decoding. */
+/** Common std::string to integer map entry for option decoding. */
 struct tab_entry {
     const char* s;
 
@@ -60,10 +60,10 @@
     }
 };
 
-/** Decode a string to an integer.
+/** Decode a std::string to an integer.
  *
- *  @param table  Array of tab_entry in ascending string order.
- *  @param s      The string to decode.
+ *  @param table  Array of tab_entry in ascending std::string order.
+ *  @param s      The std::string to decode.
  */
 template<typename T, std::size_t N>
 static int
@@ -146,9 +146,9 @@
 #define INDENT \
 "                                    "
 
-/** Print string from a string to integer mapping table.
+/** Print std::string from a std::string to integer mapping table.
  *
- *  @param table  Array of tab_entry in ascending string order.
+ *  @param table  Array of tab_entry in ascending std::string order.
  */
 template<typename T>
 static char
@@ -275,8 +275,8 @@
 		    cerr << argv[0] << ": need ':' when setting prefix\n";
 		    exit(1);
 		}
-		string prefix(optarg, colon - optarg);
-		string termprefix(colon + 1);
+		std::string prefix(optarg, colon - optarg);
+		std::string termprefix(colon + 1);
 		if (c == 'b') {
 		    parser.add_boolean_prefix(prefix, termprefix);
 		} else {
@@ -347,7 +347,7 @@
 	flags = Xapian::QueryParser::FLAG_DEFAULT;
     }
     Xapian::Query query = parser.parse_query(argv[optind], flags);
-    const string & correction = parser.get_corrected_query_string();
+    const std::string & correction = parser.get_corrected_query_string();
     if (!correction.empty())
 	cout << "Did you mean: " << correction << "\n\n";
 
@@ -433,7 +433,7 @@
     cout << "MSet:\n";
     for (Xapian::MSetIterator i = mset.begin(); i != mset.end(); ++i) {
 	Xapian::Document doc = i.get_document();
-	string data = doc.get_data();
+	std::string data = doc.get_data();
 	cout << *i << ": [" << i.get_weight() << "]\n" << data << "\n";
     }
     cout << flush;
diff -ur xapian-core-1.4.21/examples/simpleexpand.cc xapian-core-1.4.21/examples/simpleexpand.cc
--- xapian-core-1.4.21/examples/simpleexpand.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/simpleexpand.cc	2022-11-08 16:44:15.444461628 +0100
@@ -60,7 +60,7 @@
     // Combine command line arguments up to "--" with spaces between
     // them, so that simple queries don't have to be quoted at the shell
     // level.
-    string query_string(argv[2]);
+    std::string query_string(argv[2]);
     argv += 3;
     while (*argv && strcmp(*argv, "--") != 0) {
 	query_string += ' ';
@@ -75,7 +75,7 @@
 	}
     }
 
-    // Parse the query string to produce a Xapian::Query object.
+    // Parse the query std::string to produce a Xapian::Query object.
     Xapian::QueryParser qp;
     Xapian::Stem stemmer("english");
     qp.set_stemmer(stemmer);
diff -ur xapian-core-1.4.21/examples/simpleindex.cc xapian-core-1.4.21/examples/simpleindex.cc
--- xapian-core-1.4.21/examples/simpleindex.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/simpleindex.cc	2022-11-08 16:44:15.444461628 +0100
@@ -59,9 +59,9 @@
     indexer.set_stemmer(stemmer);
     indexer.set_stemming_strategy(indexer.STEM_SOME_FULL_POS);
 
-    string para;
+    std::string para;
     while (true) {
-	string line;
+	std::string line;
 	if (cin.eof()) {
 	    if (para.empty()) break;
 	} else {
diff -ur xapian-core-1.4.21/examples/simplesearch.cc xapian-core-1.4.21/examples/simplesearch.cc
--- xapian-core-1.4.21/examples/simplesearch.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/simplesearch.cc	2022-11-08 16:44:15.448461615 +0100
@@ -62,14 +62,14 @@
     // Combine the rest of the command line arguments with spaces between
     // them, so that simple queries don't have to be quoted at the shell
     // level.
-    string query_string(argv[2]);
+    std::string query_string(argv[2]);
     argv += 3;
     while (*argv) {
 	query_string += ' ';
 	query_string += *argv++;
     }
 
-    // Parse the query string to produce a Xapian::Query object.
+    // Parse the query std::string to produce a Xapian::Query object.
     Xapian::QueryParser qp;
     Xapian::Stem stemmer("english");
     qp.set_stemmer(stemmer);
diff -ur xapian-core-1.4.21/examples/xapian-metadata.cc xapian-core-1.4.21/examples/xapian-metadata.cc
--- xapian-core-1.4.21/examples/xapian-metadata.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/xapian-metadata.cc	2022-11-08 16:44:15.448461615 +0100
@@ -68,7 +68,7 @@
     } else if (strcmp(command, "list") == 0) {
 	if (argc != 3 && argc != 4) goto syntax_error;
 	Xapian::Database db(argv[2]);
-	string prefix;
+	std::string prefix;
 	if (argc == 4) prefix = argv[3];
 	for (Xapian::TermIterator t = db.metadata_keys_begin(prefix);
 	     t != db.metadata_keys_end(prefix);
diff -ur xapian-core-1.4.21/examples/xapian-pos.cc xapian-core-1.4.21/examples/xapian-pos.cc
--- xapian-core-1.4.21/examples/xapian-pos.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/examples/xapian-pos.cc	2022-11-08 16:44:15.444461628 +0100
@@ -59,7 +59,7 @@
 
     Xapian::PositionIterator p;
 
-    string term;
+    std::string term;
 
   public:
     Pos(const string& term_, const Xapian::PositionIterator& p_)
@@ -172,7 +172,7 @@
 	exit(1);
     }
 
-    vector<Pos*> heap;
+    std::vector<Pos*> heap;
 
     Xapian::Database db(argv[optind]);
 
diff -ur xapian-core-1.4.21/expand/esetinternal.cc xapian-core-1.4.21/expand/esetinternal.cc
--- xapian-core-1.4.21/expand/esetinternal.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/expand/esetinternal.cc	2022-11-08 16:44:15.588461116 +0100
@@ -47,7 +47,7 @@
 string
 Internal::ExpandTerm::get_description() const
 {
-    string desc("ExpandTerm(");
+    std::string desc("ExpandTerm(");
     desc += str(wt);
     desc += ", ";
     description_append(desc, term);
@@ -75,7 +75,7 @@
 
     const set<Xapian::docid> & docids = rset.internal->get_items();
 
-    vector<TermList*> termlists;
+    std::vector<TermList*> termlists;
     termlists.reserve(docids.size());
 
     try {
@@ -167,7 +167,7 @@
 
 	if (tree->at_end()) break;
 
-	string term = tree->get_termname();
+	std::string term = tree->get_termname();
 
 	// If there's an ExpandDecider, see if it accepts the term.
 	if (edecider && !(*edecider)(term)) continue;
@@ -212,10 +212,10 @@
 string
 ESet::Internal::get_description() const
 {
-    string desc("ESet::Internal(ebound=");
+    std::string desc("ESet::Internal(ebound=");
     desc += str(ebound);
 
-    vector<Xapian::Internal::ExpandTerm>::const_iterator i;
+    std::vector<Xapian::Internal::ExpandTerm>::const_iterator i;
     for (i = items.begin(); i != items.end(); ++i) {
 	desc += ", ";
 	desc += i->get_description();
@@ -260,7 +260,7 @@
 std::string
 ESet::get_description() const
 {
-    string desc = "ESet(";
+    std::string desc = "ESet(";
     if (internal.get())
 	desc += internal->get_description();
     desc += ')';
@@ -283,7 +283,7 @@
 std::string
 ESetIterator::get_description() const
 {
-    string desc = "ESetIterator(";
+    std::string desc = "ESetIterator(";
     if (eset.internal.get())
 	desc += str(eset.internal->items.size() - off_from_end);
     desc += ')';
diff -ur xapian-core-1.4.21/expand/esetinternal.h xapian-core-1.4.21/expand/esetinternal.h
--- xapian-core-1.4.21/expand/esetinternal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/expand/esetinternal.h	2022-11-08 16:44:01.092512649 +0100
@@ -67,7 +67,7 @@
 	return term > o.term;
     }
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -106,7 +106,7 @@
 		Xapian::Internal::ExpandWeight & eweight,
 		double min_wt);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/expand/ortermlist.cc xapian-core-1.4.21/expand/ortermlist.cc
--- xapian-core-1.4.21/expand/ortermlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/expand/ortermlist.cc	2022-11-08 16:44:15.592461103 +0100
@@ -148,7 +148,7 @@
 }
 
 TermList *
-OrTermList::skip_to(const string & term)
+OrTermList::skip_to(const std::string & term)
 {
     LOGCALL(EXPAND, TermList *, "OrTermList::skip_to", term);
     handle_prune(left, left->skip_to(term));
diff -ur xapian-core-1.4.21/expand/ortermlist.h xapian-core-1.4.21/expand/ortermlist.h
--- xapian-core-1.4.21/expand/ortermlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/expand/ortermlist.h	2022-11-08 16:44:01.092512649 +0100
@@ -37,7 +37,7 @@
     /** The current term for left and right respectively.
      *
      *  Until next() is first called, these will be empty strings.  Once next()
-     *  has been called, they won't be empty (since the empty string isn't a
+     *  has been called, they won't be empty (since the empty std::string isn't a
      *  valid term).
      */
     std::string left_current, right_current;
diff -ur xapian-core-1.4.21/geospatial/geoencode.cc xapian-core-1.4.21/geospatial/geoencode.cc
--- xapian-core-1.4.21/geospatial/geoencode.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/geospatial/geoencode.cc	2022-11-08 16:44:15.324462056 +0100
@@ -70,7 +70,7 @@
 };
 
 bool
-GeoEncode::encode(double lat, double lon, string & result)
+GeoEncode::encode(double lat, double lon, std::string & result)
 {
     // Check range of latitude.
     if (rare(lat < -90.0 || lat > 90.0)) {
diff -ur xapian-core-1.4.21/geospatial/geoencode.h xapian-core-1.4.21/geospatial/geoencode.h
--- xapian-core-1.4.21/geospatial/geoencode.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/geospatial/geoencode.h	2022-11-08 16:44:00.904513317 +0100
@@ -36,11 +36,11 @@
  * @param lon The longitude coordinate in degrees (any range is valid -
  *            longitudes will be wrapped).  Note that decoding will return
  *            longitudes in the range 0 <= value < 360.
- * @param result The string to append the result to.
+ * @param result The std::string to append the result to.
  *
  * @returns true if the encoding was successful, false if there was an error.
  * If there was an error, the result value will be unmodified.  The only cause
- * of error is out-of-range latitudes.  If there was no error, the string will
+ * of error is out-of-range latitudes.  If there was no error, the std::string will
  * have been extended by 6 bytes.
  */
 extern bool
@@ -65,7 +65,7 @@
 
 /** Decode a coordinate from a string.
  *
- * @param value The string to decode.  This must be at least 2 bytes long (this
+ * @param value The std::string to decode.  This must be at least 2 bytes long (this
  *              constraint is not checked).
  * @param lat_ref A reference to a value to return the latitude in.
  * @param lon_ref A reference to a value to return the longitude in.
diff -ur xapian-core-1.4.21/geospatial/latlongcoord.cc xapian-core-1.4.21/geospatial/latlongcoord.cc
--- xapian-core-1.4.21/geospatial/latlongcoord.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/geospatial/latlongcoord.cc	2022-11-08 16:44:15.320462069 +0100
@@ -44,7 +44,7 @@
 }
 
 void
-LatLongCoord::unserialise(const string & serialised)
+LatLongCoord::unserialise(const std::string & serialised)
 {
     const char * ptr = serialised.data();
     const char * end = ptr + serialised.size();
@@ -74,7 +74,7 @@
 string
 LatLongCoord::serialise() const
 {
-    string result;
+    std::string result;
     GeoEncode::encode(latitude, longitude, result);
     return result;
 }
@@ -82,7 +82,7 @@
 string
 LatLongCoord::get_description() const
 {
-    string res("Xapian::LatLongCoord(");
+    std::string res("Xapian::LatLongCoord(");
     res += str(latitude);
     res += ", ";
     res += str(longitude);
@@ -91,7 +91,7 @@
 }
 
 void
-LatLongCoords::unserialise(const string & serialised)
+LatLongCoords::unserialise(const std::string & serialised)
 {
     const char * ptr = serialised.data();
     const char * end_ptr = ptr + serialised.size();
@@ -105,8 +105,8 @@
 string
 LatLongCoords::serialise() const
 {
-    string result;
-    vector<LatLongCoord>::const_iterator coord;
+    std::string result;
+    std::vector<LatLongCoord>::const_iterator coord;
     for (coord = coords.begin(); coord != coords.end(); ++coord)
     {
 	GeoEncode::encode(coord->latitude, coord->longitude, result);
@@ -117,8 +117,8 @@
 string
 LatLongCoords::get_description() const
 {
-    string res("Xapian::LatLongCoords(");
-    vector<LatLongCoord>::const_iterator coord;
+    std::string res("Xapian::LatLongCoords(");
+    std::vector<LatLongCoord>::const_iterator coord;
     for (coord = coords.begin(); coord != coords.end(); ++coord) {
 	if (coord != coords.begin()) {
 	    res += ", ";
diff -ur xapian-core-1.4.21/geospatial/latlong_distance_keymaker.cc xapian-core-1.4.21/geospatial/latlong_distance_keymaker.cc
--- xapian-core-1.4.21/geospatial/latlong_distance_keymaker.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/geospatial/latlong_distance_keymaker.cc	2022-11-08 16:44:15.324462056 +0100
@@ -33,7 +33,7 @@
 string
 LatLongDistanceKeyMaker::operator()(const Document &doc) const
 {
-    string val(doc.get_value(slot));
+    std::string val(doc.get_value(slot));
     if (val.empty()) {
 	return defkey;
     }
diff -ur xapian-core-1.4.21/geospatial/latlong_posting_source.cc xapian-core-1.4.21/geospatial/latlong_posting_source.cc
--- xapian-core-1.4.21/geospatial/latlong_posting_source.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/geospatial/latlong_posting_source.cc	2022-11-08 16:44:15.324462056 +0100
@@ -53,13 +53,13 @@
 static void
 validate_postingsource_params(double k1, double k2) {
     if (k1 <= 0) {
-	string msg("k1 parameter to LatLongDistancePostingSource must be "
+	std::string msg("k1 parameter to LatLongDistancePostingSource must be "
 		   "greater than 0; was ");
 	msg += str(k1);
 	throw InvalidArgumentError(msg);
     }
     if (k2 <= 0) {
-	string msg("k2 parameter to LatLongDistancePostingSource must be "
+	std::string msg("k2 parameter to LatLongDistancePostingSource must be "
 		   "greater than 0; was ");
 	msg += str(k2);
 	throw InvalidArgumentError(msg);
@@ -194,11 +194,11 @@
 string
 LatLongDistancePostingSource::serialise() const
 {
-    string serialised_centre = centre.serialise();
-    string metric_name = metric->name();
-    string serialised_metric = metric->serialise();
+    std::string serialised_centre = centre.serialise();
+    std::string metric_name = metric->name();
+    std::string serialised_metric = metric->serialise();
 
-    string result = encode_length(get_slot());
+    std::string result = encode_length(get_slot());
     result += encode_length(serialised_centre.size());
     result += serialised_centre;
     result += encode_length(metric_name.size());
@@ -212,7 +212,7 @@
 }
 
 LatLongDistancePostingSource *
-LatLongDistancePostingSource::unserialise_with_registry(const string &s,
+LatLongDistancePostingSource::unserialise_with_registry(const std::string &s,
 					     const Registry & registry) const
 {
     const char * p = s.data();
@@ -222,13 +222,13 @@
     decode_length(&p, end, new_slot);
     size_t len;
     decode_length_and_check(&p, end, len);
-    string new_serialised_centre(p, len);
+    std::string new_serialised_centre(p, len);
     p += len;
     decode_length_and_check(&p, end, len);
-    string new_metric_name(p, len);
+    std::string new_metric_name(p, len);
     p += len;
     decode_length_and_check(&p, end, len);
-    string new_serialised_metric(p, len);
+    std::string new_serialised_metric(p, len);
     p += len;
     double new_max_range = unserialise_double(&p, end);
     double new_k1 = unserialise_double(&p, end);
@@ -243,7 +243,7 @@
     const Xapian::LatLongMetric * metric_type =
 	    registry.get_lat_long_metric(new_metric_name);
     if (metric_type == NULL) {
-	string msg("LatLongMetric ");
+	std::string msg("LatLongMetric ");
 	msg += new_metric_name;
 	msg += " not registered";
 	throw InvalidArgumentError(msg);
@@ -272,7 +272,7 @@
 string
 LatLongDistancePostingSource::get_description() const
 {
-    string result("Xapian::LatLongDistancePostingSource(slot=");
+    std::string result("Xapian::LatLongDistancePostingSource(slot=");
     result += str(get_slot());
     result += ")";
     return result;
diff -ur xapian-core-1.4.21/include/xapian/compactor.h xapian-core-1.4.21/include/xapian/compactor.h
--- xapian-core-1.4.21/include/xapian/compactor.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/compactor.h	2022-11-08 16:44:00.980513047 +0100
@@ -170,7 +170,7 @@
      *  may change in the future.
      *
      *  Since 1.4.6, an implementation of this method can return an empty
-     *  string to indicate that the appropriate result is to not set a value
+     *  std::string to indicate that the appropriate result is to not set a value
      *  for this user metadata key in the output database.  In older versions,
      *  you should not return an empty string.
      *
diff -ur xapian-core-1.4.21/include/xapian/constants.h xapian-core-1.4.21/include/xapian/constants.h
--- xapian-core-1.4.21/include/xapian/constants.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/constants.h	2022-11-08 16:44:00.984513032 +0100
@@ -181,7 +181,7 @@
 /** Use the "in memory" backend.
  *
  *  The filename is currently ignored when this flag is used, but an empty
- *  string should be passed to allow for future expansion.
+ *  std::string should be passed to allow for future expansion.
  *
  *  A new empty database is created, so when creating a Database object this
  *  creates an empty read-only database - sometimes useful to avoid special
diff -ur xapian-core-1.4.21/include/xapian/database.h xapian-core-1.4.21/include/xapian/database.h
--- xapian-core-1.4.21/include/xapian/database.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/database.h	2022-11-08 16:44:00.976513061 +0100
@@ -205,7 +205,7 @@
 	 */
 	virtual void close();
 
-	/// Return a string describing this object.
+	/// Return a std::string describing this object.
 	virtual std::string get_description() const;
 
 	/** An iterator pointing to the start of the postlist
@@ -467,7 +467,7 @@
 	 *  but this behaviour may change in the future.
 	 *
 	 *  If there is no piece of metadata associated with the specified
-	 *  key, an empty string is returned (this applies even for backends
+	 *  key, an empty std::string is returned (this applies even for backends
 	 *  which don't support metadata).
 	 *
 	 *  Empty keys are not valid, and specifying one will cause an
@@ -518,7 +518,7 @@
 	 *  If the backend does not support UUIDs or this database has no
 	 *  subdatabases, the UUID will be empty.
 	 *
-	 *  If this database has multiple sub-databases, the UUID string will
+	 *  If this database has multiple sub-databases, the UUID std::string will
 	 *  contain the UUIDs of all the sub-databases.
 	 */
 	std::string get_uuid() const;
@@ -1273,7 +1273,7 @@
 	 */
 	void set_metadata(const std::string & key, const std::string & metadata);
 
-	/// Return a string describing this object.
+	/// Return a std::string describing this object.
 	std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/document.h xapian-core-1.4.21/include/xapian/document.h
--- xapian-core-1.4.21/include/xapian/document.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/document.h	2022-11-08 16:44:00.984513032 +0100
@@ -100,7 +100,7 @@
 
 	/** Get value by number.
 	 *
-	 *  Returns an empty string if no value with the given number is present
+	 *  Returns an empty std::string if no value with the given number is present
 	 *  in the document.
 	 *
 	 *  @param slot The number of the value.
@@ -294,11 +294,11 @@
 	 */
 	std::string serialise() const;
 
-	/** Unserialise a document from a string produced by serialise().
+	/** Unserialise a document from a std::string produced by serialise().
 	 */
 	static Document unserialise(const std::string &serialised);
 
-	/// Return a string describing this object.
+	/// Return a std::string describing this object.
 	std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/enquire.h xapian-core-1.4.21/include/xapian/enquire.h
--- xapian-core-1.4.21/include/xapian/enquire.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/enquire.h	2022-11-08 16:44:00.988513019 +0100
@@ -109,7 +109,7 @@
 	/// Test if a given document in the relevance set.
 	bool contains(const Xapian::MSetIterator & i) const { return contains(*i); }
 
-	/// Return a string describing this object.
+	/// Return a std::string describing this object.
 	std::string get_description() const;
 };
 
@@ -270,7 +270,7 @@
 	 *
 	 *  get_expansion_scheme("trad");
 	 *
-	 *  @param eweightname_  A string in lowercase specifying the name of
+	 *  @param eweightname_  A std::string in lowercase specifying the name of
 	 *                       the scheme to be used. The following schemes
 	 *                       are currently available:
 	 *                       "bo1" : The Bo1 scheme for query expansion.
@@ -383,7 +383,7 @@
 
 	/** Set the sorting to be by value only.
 	 *
-	 *  Note that sorting by values uses a string comparison, so to use
+	 *  Note that sorting by values uses a std::string comparison, so to use
 	 *  this to sort by a numeric value you'll need to store the numeric
 	 *  values in a manner which sorts appropriately.  For example, you
 	 *  could use Xapian::sortable_serialise() (which works for floating
@@ -407,7 +407,7 @@
 	/** Set the sorting to be by value, then by relevance for documents
 	 *  with the same value.
 	 *
-	 *  Note that sorting by values uses a string comparison, so to use
+	 *  Note that sorting by values uses a std::string comparison, so to use
 	 *  this to sort by a numeric value you'll need to store the numeric
 	 *  values in a manner which sorts appropriately.  For example, you
 	 *  could use Xapian::sortable_serialise() (which works for floating
@@ -433,7 +433,7 @@
 
 	/** Set the sorting to be by relevance then value.
 	 *
-	 *  Note that sorting by values uses a string comparison, so to use
+	 *  Note that sorting by values uses a std::string comparison, so to use
 	 *  this to sort by a numeric value you'll need to store the numeric
 	 *  values in a manner which sorts appropriately.  For example, you
 	 *  could use Xapian::sortable_serialise() (which works for floating
@@ -743,7 +743,7 @@
 	    return TermIterator();
 	}
 
-	/// Return a string describing this object.
+	/// Return a std::string describing this object.
 	std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/error.h xapian-core-1.4.21/include/xapian/error.h
--- xapian-core-1.4.21/include/xapian/error.h	2022-09-22 07:29:21.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/error.h	2022-11-08 16:44:01.004512962 +0100
@@ -56,9 +56,9 @@
      */
     std::string context;
 
-    /** The error string derived from my_errno.
+    /** The error std::string derived from my_errno.
      *
-     *  This string is generated from my_errno lazily.
+     *  This std::string is generated from my_errno lazily.
      */
     mutable std::string error_string;
 
@@ -134,15 +134,15 @@
 	return context;
     }
 
-    /** Returns any system error string associated with this exception.
+    /** Returns any system error std::string associated with this exception.
      *
-     *  The system error string may come from errno, h_errno (on UNIX), or
+     *  The system error std::string may come from errno, h_errno (on UNIX), or
      *  GetLastError() (on MS Windows).  If there is no associated system
      *  error string, NULL is returned.
      */
     const char * get_error_string() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -201,7 +201,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     AssertionError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: LogicError(msg_, context_, "\000AssertionError", error_string_) {}
@@ -243,7 +243,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     InvalidArgumentError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: LogicError(msg_, context_, "\001InvalidArgumentError", error_string_) {}
@@ -285,7 +285,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     InvalidOperationError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: LogicError(msg_, context_, "\002InvalidOperationError", error_string_) {}
@@ -327,7 +327,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     UnimplementedError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: LogicError(msg_, context_, "\003UnimplementedError", error_string_) {}
@@ -369,7 +369,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\004DatabaseError", error_string_) {}
@@ -411,7 +411,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseCorruptError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\005DatabaseCorruptError", error_string_) {}
@@ -453,7 +453,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseCreateError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\006DatabaseCreateError", error_string_) {}
@@ -495,7 +495,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseLockError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\007DatabaseLockError", error_string_) {}
@@ -541,7 +541,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseModifiedError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\010DatabaseModifiedError", error_string_) {}
@@ -583,7 +583,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseOpeningError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\011DatabaseOpeningError", error_string_) {}
@@ -634,7 +634,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseVersionError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseOpeningError(msg_, context_, "\012DatabaseVersionError", error_string_) {}
@@ -676,7 +676,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DocNotFoundError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\013DocNotFoundError", error_string_) {}
@@ -721,7 +721,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     FeatureUnavailableError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\014FeatureUnavailableError", error_string_) {}
@@ -763,7 +763,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     InternalError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\015InternalError", error_string_) {}
@@ -805,7 +805,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     NetworkError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\016NetworkError", error_string_) {}
@@ -847,7 +847,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     NetworkTimeoutError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: NetworkError(msg_, context_, "\017NetworkTimeoutError", error_string_) {}
@@ -882,14 +882,14 @@
 	: NetworkError(msg_, context_, type_, errno_) {}
 };
 
-/** Indicates a query string can't be parsed.
+/** Indicates a query std::string can't be parsed.
  */
 class XAPIAN_VISIBILITY_DEFAULT QueryParserError : public RuntimeError {
   public:
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     QueryParserError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\020QueryParserError", error_string_) {}
@@ -931,7 +931,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     SerialisationError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\021SerialisationError", error_string_) {}
@@ -973,7 +973,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     RangeError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\022RangeError", error_string_) {}
@@ -1015,7 +1015,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     WildcardError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: RuntimeError(msg_, context_, "\023WildcardError", error_string_) {}
@@ -1057,7 +1057,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseNotFoundError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseOpeningError(msg_, context_, "\024DatabaseNotFoundError", error_string_) {}
@@ -1099,7 +1099,7 @@
     /** @private @internal
      *  @brief Private constructor for use by remote backend.
      *
-     *  @param error_string_	Optional string describing error.  May be NULL.
+     *  @param error_string_	Optional std::string describing error.  May be NULL.
      */
     DatabaseClosedError(const std::string &msg_, const std::string &context_, const char * error_string_)
 	: DatabaseError(msg_, context_, "\025DatabaseClosedError", error_string_) {}
diff -ur xapian-core-1.4.21/include/xapian/eset.h xapian-core-1.4.21/include/xapian/eset.h
--- xapian-core-1.4.21/include/xapian/eset.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/eset.h	2022-11-08 16:44:00.972513076 +0100
@@ -106,7 +106,7 @@
     /** Return iterator pointing to the last object in this ESet. */
     ESetIterator back() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal ESet is what the C++ STL calls a container.
@@ -265,7 +265,7 @@
     /** Get the weight for the current position. */
     double get_weight() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/geospatial.h xapian-core-1.4.21/include/xapian/geospatial.h
--- xapian-core-1.4.21/include/xapian/geospatial.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/geospatial.h	2022-11-08 16:44:00.992513004 +0100
@@ -115,11 +115,11 @@
      */
     LatLongCoord(double latitude_, double longitude_);
 
-    /** Unserialise a string and set this object to its coordinate.
+    /** Unserialise a std::string and set this object to its coordinate.
      *
-     *  @param serialised the string to unserialise the coordinate from.
+     *  @param serialised the std::string to unserialise the coordinate from.
      *
-     *  @exception Xapian::SerialisationError if the string does not contain
+     *  @exception Xapian::SerialisationError if the std::string does not contain
      *  a valid serialised latitude-longitude pair, or contains extra data at
      *  the end of it.
      */
@@ -133,7 +133,7 @@
      *  to point to the end of the data representing the coordinate.
      *  @param end A pointer to the end of the string.
      *
-     *  @exception Xapian::SerialisationError if the string does not start with
+     *  @exception Xapian::SerialisationError if the std::string does not start with
      *  a valid serialised latitude-longitude pair.
      */
     void unserialise(const char ** ptr, const char * end);
@@ -154,7 +154,7 @@
 	return (longitude < other.longitude);
     }
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -271,11 +271,11 @@
 	coords.push_back(coord);
     }
 
-    /** Unserialise a string and set this object to the coordinates in it.
+    /** Unserialise a std::string and set this object to the coordinates in it.
      *
-     *  @param serialised the string to unserialise the coordinates from.
+     *  @param serialised the std::string to unserialise the coordinates from.
      *
-     *  @exception Xapian::SerialisationError if the string does not contain
+     *  @exception Xapian::SerialisationError if the std::string does not contain
      *  a valid serialised latitude-longitude pair, or contains junk at the end
      *  of it.
      */
@@ -285,7 +285,7 @@
      */
     std::string serialise() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -379,7 +379,7 @@
      */
     virtual std::string serialise() const = 0;
 
-    /** Create object given string serialisation returned by serialise().
+    /** Create object given std::string serialisation returned by serialise().
      *
      *  @param serialised A serialised instance of this LatLongMetric subclass.
      */
diff -ur xapian-core-1.4.21/include/xapian/keymaker.h xapian-core-1.4.21/include/xapian/keymaker.h
--- xapian-core-1.4.21/include/xapian/keymaker.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/keymaker.h	2022-11-08 16:44:00.972513076 +0100
@@ -50,7 +50,7 @@
     /// Default constructor.
     KeyMaker() { }
 
-    /** Build a key string for a Document.
+    /** Build a key std::string for a Document.
      *
      *  These keys can be used for sorting or collapsing matching documents.
      *
diff -ur xapian-core-1.4.21/include/xapian/matchspy.h xapian-core-1.4.21/include/xapian/matchspy.h
--- xapian-core-1.4.21/include/xapian/matchspy.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/matchspy.h	2022-11-08 16:44:01.000512975 +0100
@@ -135,7 +135,7 @@
      *  method in your subclass as shown here:
      *  https://trac.xapian.org/ticket/554#comment:1
      *
-     *  @param serialised	A string containing the serialised results.
+     *  @param serialised	A std::string containing the serialised results.
      *  @param context	Registry object to use for unserialisation to permit
      *			MatchSpy subclasses with sub-MatchSpy objects to be
      *			implemented.
@@ -161,11 +161,11 @@
      *  can use the default implementation which simply throws
      *  Xapian::UnimplementedError.
      *
-     *  @param serialised	A string containing the serialised results.
+     *  @param serialised	A std::string containing the serialised results.
      */
     virtual void merge_results(const std::string & serialised);
 
-    /** Return a string describing this object.
+    /** Return a std::string describing this object.
      *
      *  This default implementation returns a generic answer, to avoid forcing
      *  those deriving their own MatchSpy subclasses from having to implement
diff -ur xapian-core-1.4.21/include/xapian/mset.h xapian-core-1.4.21/include/xapian/mset.h
--- xapian-core-1.4.21/include/xapian/mset.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/mset.h	2022-11-08 16:44:00.988513019 +0100
@@ -177,9 +177,9 @@
 	 *  the time taken to generate a snippet.
 	 */
 	SNIPPET_EXHAUSTIVE = 2,
-	/** Return the empty string if no term got matched.
+	/** Return the empty std::string if no term got matched.
 	 *
-	 *  If enabled, snippet() returns an empty string if not a single match
+	 *  If enabled, snippet() returns an empty std::string if not a single match
 	 *  was found in text. If not enabled, snippet() returns a (sub)string
 	 *  of text without any highlighted terms.
 	 */
@@ -297,7 +297,7 @@
     /** Return iterator pointing to the last object in this MSet. */
     MSetIterator back() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal MSet is what the C++ STL calls a container.
@@ -469,7 +469,7 @@
 
     /** Return the collapse key for the current position.
      *
-     *  If collapsing isn't in use, an empty string will be returned.
+     *  If collapsing isn't in use, an empty std::string will be returned.
      */
     std::string get_collapse_key() const;
 
@@ -494,7 +494,7 @@
 
     /** Return the sort key for the current position.
      *
-     *  If sorting didn't use a key then an empty string will be returned.
+     *  If sorting didn't use a key then an empty std::string will be returned.
      *
      *  @since Added in Xapian 1.4.6.
      */
@@ -515,7 +515,7 @@
 	return mset.convert_to_percent(get_weight());
     }
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/positioniterator.h xapian-core-1.4.21/include/xapian/positioniterator.h
--- xapian-core-1.4.21/include/xapian/positioniterator.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/positioniterator.h	2022-11-08 16:44:01.000512975 +0100
@@ -107,7 +107,7 @@
      */
     void skip_to(Xapian::termpos termpos);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal PositionIterator is what the C++ STL calls an
diff -ur xapian-core-1.4.21/include/xapian/postingiterator.h xapian-core-1.4.21/include/xapian/postingiterator.h
--- xapian-core-1.4.21/include/xapian/postingiterator.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/postingiterator.h	2022-11-08 16:44:00.984513032 +0100
@@ -128,7 +128,7 @@
      */
     void skip_to(Xapian::docid did);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal PostingIterator is what the C++ STL calls an
diff -ur xapian-core-1.4.21/include/xapian/postingsource.h xapian-core-1.4.21/include/xapian/postingsource.h
--- xapian-core-1.4.21/include/xapian/postingsource.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/postingsource.h	2022-11-08 16:44:01.000512975 +0100
@@ -295,7 +295,7 @@
      */
     virtual std::string serialise() const;
 
-    /** Create object given string serialisation returned by serialise().
+    /** Create object given std::string serialisation returned by serialise().
      *
      *  Note that the returned object will be deallocated by Xapian after use
      *  with "delete".  If you want to handle the deletion in a special way
@@ -311,7 +311,7 @@
      */
     virtual PostingSource * unserialise(const std::string &serialised) const;
 
-    /** Create object given string serialisation returned by serialise().
+    /** Create object given std::string serialisation returned by serialise().
      *
      *  Note that the returned object will be deallocated by Xapian after use
      *  with "delete".  If you want to handle the deletion in a special way
@@ -353,7 +353,7 @@
      */
     virtual void init(const Database & db) = 0;
 
-    /** Return a string describing this object.
+    /** Return a std::string describing this object.
      *
      *  This default implementation returns a generic answer.  This default
      *  it provided to avoid forcing those deriving their own PostingSource
diff -ur xapian-core-1.4.21/include/xapian/query.h xapian-core-1.4.21/include/xapian/query.h
--- xapian-core-1.4.21/include/xapian/query.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/query.h	2022-11-08 16:44:00.996512990 +0100
@@ -299,7 +299,7 @@
 	 *
 	 *  If OP_WILDCARD would expand to more than its expansion limit, the
 	 *  most frequent terms are taken.  This approach works well for cases
-	 *  such as expanding a partial term at the end of a query string which
+	 *  such as expanding a partial term at the end of a query std::string which
 	 *  the user hasn't finished typing yet - as well as being less expense
 	 *  to evaluate than the full expansion, using only the most frequent
 	 *  terms tends to give better results too.
@@ -343,7 +343,7 @@
 
     /** Construct a Query object for a term.
      *
-     *  @param term The term.  An empty string constructs a query matching
+     *  @param term The term.  An empty std::string constructs a query matching
      *		    all documents (@a MatchAll is a static instance of this).
      *  @param wqf  The within-query frequency. (default: 1)
      *  @param pos  The query position.  Currently this is mainly used to
@@ -528,9 +528,9 @@
     /** Serialise this object into a string. */
     std::string serialise() const;
 
-    /** Unserialise a string and return a Query object.
+    /** Unserialise a std::string and return a Query object.
      *
-     *  @param serialised	the string to unserialise.
+     *  @param serialised	the std::string to unserialise.
      *  @param reg		Xapian::Registry object to use to unserialise
      *				user-subclasses of Xapian::PostingSource
      *				(default: standard registry).
@@ -551,7 +551,7 @@
       */
     const Query get_subquery(size_t n) const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** Combine with another Xapian::Query object using OP_AND.
diff -ur xapian-core-1.4.21/include/xapian/queryparser.h xapian-core-1.4.21/include/xapian/queryparser.h
--- xapian-core-1.4.21/include/xapian/queryparser.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/queryparser.h	2022-11-08 16:44:00.996512990 +0100
@@ -1,5 +1,5 @@
 /** @file
- * @brief parsing a user query string to build a Xapian::Query object
+ * @brief parsing a user query std::string to build a Xapian::Query object
  */
 /* Copyright (C) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2021 Olly Betts
  * Copyright (C) 2010 Adam Sjøgren
@@ -68,7 +68,7 @@
     /// Class has virtual methods, so provide a virtual destructor.
     virtual ~Stopper() { }
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     virtual std::string get_description() const;
 
     /** Start reference counting this object.
@@ -152,7 +152,7 @@
      */
     Xapian::valueno slot;
 
-    /** The prefix (or suffix with RP_SUFFIX) string to look for. */
+    /** The prefix (or suffix with RP_SUFFIX) std::string to look for. */
     std::string str;
 
     /** Flags.
@@ -175,7 +175,7 @@
     /** Constructor.
      *
      *  @param slot_	Which value slot to generate ranges over.
-     *  @param str_	A string to look for to recognise values as belonging
+     *  @param str_	A std::string to look for to recognise values as belonging
      *			to this range (as a prefix by default, or as a suffix
      *			if flags Xapian::RP_SUFFIX is specified).
      *  @param flags_	Zero or more of the following flags, combined with
@@ -210,7 +210,7 @@
      *  @param begin	The start of the range as specified in the query string
      *			by the user.
      *  @param end	The end of the range as specified in the query string
-     *			by the user (empty string for no upper limit).
+     *			by the user (empty std::string for no upper limit).
      *
      *  @return		An OP_VALUE_RANGE Query object (or if end.empty(), an
      *			OP_VALUE_GE Query object).  Or if the range isn't one
@@ -277,7 +277,7 @@
      *
      *  @param slot_	The value slot number to query.
      *
-     *  @param str_	A string to look for to recognise values as belonging
+     *  @param str_	A std::string to look for to recognise values as belonging
      *			to this date range.
      *
      *  @param flags_	Zero or more of the following flags, combined with
@@ -296,7 +296,7 @@
      *			    years (default: 1970, so 1/1/69 is 2069 while
      *			    1/1/70 is 1970).
      *
-     *  The string supplied in str_ is used by @a operator() to decide whether
+     *  The std::string supplied in str_ is used by @a operator() to decide whether
      *  the pair of strings supplied to it constitute a valid range.  If
      *  prefix_ is true, the first value in a range must begin with str_ (and
      *  the second value may optionally begin with str_);
@@ -346,7 +346,7 @@
      *
      *  @param slot_    The value slot number to query.
      *
-     *  @param str_     A string to look for to recognise values as belonging
+     *  @param str_     A std::string to look for to recognise values as belonging
      *                  to this numeric range.
      *
      *  @param flags_	Zero or more of the following flags, combined with
@@ -359,7 +359,7 @@
      *			   the start (e.g. date:1/1/1980..31/12/1989), and a
      *			   suffix only on the end (e.g. 2..12kg).
      *
-     *  The string supplied in str_ is used by @a operator() to decide whether
+     *  The std::string supplied in str_ is used by @a operator() to decide whether
      *  the pair of strings supplied to it constitute a valid range.  If
      *  prefix_ is true, the first value in a range must begin with str_ (and
      *  the second value may optionally begin with str_);
@@ -419,7 +419,7 @@
     /** Check for a valid range of this type.
      *
      *  @param[in,out] begin	The start of the range as specified in the query
-     *				string by the user.  This parameter is a
+     *				std::string by the user.  This parameter is a
      *				non-const reference so the ValueRangeProcessor
      *				can modify it to return the value to start the
      *				range with.
@@ -457,7 +457,7 @@
     }
 };
 
-/** Handle a string range.
+/** Handle a std::string range.
  *
  *  The end points can be any strings.
  *
@@ -471,7 +471,7 @@
     /** Whether to look for @a str as a prefix or suffix. */
     bool prefix;
 
-    /** The prefix (or suffix if prefix==false) string to look for. */
+    /** The prefix (or suffix if prefix==false) std::string to look for. */
     std::string str;
 
   public:
@@ -485,7 +485,7 @@
     /** Constructor.
      *
      *  @param slot_	The value number to return from operator().
-     *  @param str_     A string to look for to recognise values as belonging
+     *  @param str_     A std::string to look for to recognise values as belonging
      *                  to this range.
      *  @param prefix_	Flag specifying whether to check for str_ as a prefix
      *			or a suffix.
@@ -494,10 +494,10 @@
 			      bool prefix_ = true)
 	: valno(slot_), prefix(prefix_), str(str_) { }
 
-    /** Check for a valid string range.
+    /** Check for a valid std::string range.
      *
      *  @param[in,out] begin	The start of the range as specified in the
-     *				query string by the user.  This parameter is a
+     *				query std::string by the user.  This parameter is a
      *				non-const reference so the ValueRangeProcessor
      *				can modify it to return the value to start the
      *				range with.
@@ -541,12 +541,12 @@
      *
      *  @param slot_	    The value number to return from operator().
      *
-     *  @param str_     A string to look for to recognise values as belonging
+     *  @param str_     A std::string to look for to recognise values as belonging
      *                  to this date range.
      *
-     *  @param prefix_  Whether to look for the string at the start or end of
-     *                  the values.  If true, the string is a prefix; if
-     *                  false, the string is a suffix (default: true).
+     *  @param prefix_  Whether to look for the std::string at the start or end of
+     *                  the values.  If true, the std::string is a prefix; if
+     *                  false, the std::string is a suffix (default: true).
      *
      *  @param prefer_mdy_  Should ambiguous dates be interpreted as
      *			    month/day/year rather than day/month/year?
@@ -556,7 +556,7 @@
      *			    years (default: 1970, so 1/1/69 is 2069 while
      *			    1/1/70 is 1970).
      *
-     *  The string supplied in str_ is used by @a operator() to decide whether
+     *  The std::string supplied in str_ is used by @a operator() to decide whether
      *  the pair of strings supplied to it constitute a valid range.  If
      *  prefix_ is true, the first value in a range must begin with str_ (and
      *  the second value may optionally begin with str_);
@@ -592,12 +592,12 @@
      *
      *  @param slot_	    The value number to return from operator().
      *
-     *  @param str_     A string to look for to recognise values as belonging
+     *  @param str_     A std::string to look for to recognise values as belonging
      *                  to this date range.
      *
-     *  @param prefix_  Whether to look for the string at the start or end of
-     *                  the values.  If true, the string is a prefix; if
-     *                  false, the string is a suffix (default: true).
+     *  @param prefix_  Whether to look for the std::string at the start or end of
+     *                  the values.  If true, the std::string is a prefix; if
+     *                  false, the std::string is a suffix (default: true).
      *
      *  @param prefer_mdy_  Should ambiguous dates be interpreted as
      *			    month/day/year rather than day/month/year?
@@ -607,7 +607,7 @@
      *			    years (default: 1970, so 1/1/69 is 2069 while
      *			    1/1/70 is 1970).
      *
-     *  The string supplied in str_ is used by @a operator() to decide whether
+     *  The std::string supplied in str_ is used by @a operator() to decide whether
      *  the pair of strings supplied to it constitute a valid range.  If
      *  prefix_ is true, the first value in a range must begin with str_ (and
      *  the second value may optionally begin with str_);
@@ -635,7 +635,7 @@
     /** Check for a valid date range.
      *
      *  @param[in,out] begin	The start of the range as specified in the
-     *				query string by the user.  This parameter is a
+     *				query std::string by the user.  This parameter is a
      *				non-const reference so the ValueRangeProcessor
      *				can modify it to return the value to start the
      *				range with.
@@ -672,14 +672,14 @@
      *
      *  @param slot_    The value number to return from operator().
      *
-     *  @param str_     A string to look for to recognise values as belonging
+     *  @param str_     A std::string to look for to recognise values as belonging
      *                  to this numeric range.
      *
-     *  @param prefix_  Whether to look for the string at the start or end of
-     *                  the values.  If true, the string is a prefix; if
-     *                  false, the string is a suffix (default: true).
+     *  @param prefix_  Whether to look for the std::string at the start or end of
+     *                  the values.  If true, the std::string is a prefix; if
+     *                  false, the std::string is a suffix (default: true).
      *
-     *  The string supplied in str_ is used by @a operator() to decide whether
+     *  The std::string supplied in str_ is used by @a operator() to decide whether
      *  the pair of strings supplied to it constitute a valid range.  If
      *  prefix_ is true, the first value in a range must begin with str_ (and
      *  the second value may optionally begin with str_);
@@ -707,7 +707,7 @@
     /** Check for a valid numeric range.
      *
      *  @param[in,out] begin	The start of the range as specified in the
-     *				query string by the user.  This parameter is a
+     *				query std::string by the user.  This parameter is a
      *				non-const reference so the ValueRangeProcessor
      *				can modify it to return the value to start the
      *				range with.
@@ -741,9 +741,9 @@
     /// Destructor.
     virtual ~FieldProcessor();
 
-    /** Convert a field-prefixed string to a Query object.
+    /** Convert a field-prefixed std::string to a Query object.
      *
-     *  @param str	The string to convert.
+     *  @param str	The std::string to convert.
      *
      *  @return	Query object corresponding to @a str.
      */
@@ -843,7 +843,7 @@
 	 *  a suggestion is returned, a corrected version of the query string
 	 *  will be built up which can be read using
 	 *  QueryParser::get_corrected_query_string().  The query returned is
-	 *  based on the uncorrected query string however - if you want a
+	 *  based on the uncorrected query std::string however - if you want a
 	 *  parsed query based on the corrected query string, you must call
 	 *  QueryParser::parse_query() again.
 	 *
@@ -1072,7 +1072,7 @@
      *	@param default_prefix  The default term prefix to use (default none).
      *		For example, you can pass "A" when parsing an "Author" field.
      *
-     *  @exception If the query string can't be parsed, then
+     *  @exception If the query std::string can't be parsed, then
      *		   Xapian::QueryParserError is thrown.  You can get an English
      *		   error message to report to the user by catching it and
      *		   calling get_msg() on the caught exception.  The current
@@ -1110,7 +1110,7 @@
      *  combined with @c Xapian::Query::OP_OR.
      *
      *  If any prefixes are specified for the empty field name (i.e. you
-     *  call this method with an empty string as the first parameter)
+     *  call this method with an empty std::string as the first parameter)
      *  these prefixes will be used for terms without a field specifier.
      *  If you do this and also specify the @c default_prefix parameter to @c
      *  parse_query(), then the @c default_prefix parameter will override.
@@ -1167,7 +1167,7 @@
      *  prefixes.  Multiple terms being generated for such a field, and
      *  combined with @c Xapian::Query::OP_OR.
      *
-     *  Calling this method with an empty string for @a field will cause
+     *  Calling this method with an empty std::string for @a field will cause
      *  a @c Xapian::InvalidArgumentError.
      *
      *  If you call @c add_prefix() and @c add_boolean_prefix() for the
@@ -1298,11 +1298,11 @@
      *  This will only be set if FLAG_SPELLING_CORRECTION is specified when
      *  QueryParser::parse_query() was last called.
      *
-     *  If there were no corrections, an empty string is returned.
+     *  If there were no corrections, an empty std::string is returned.
      */
     std::string get_corrected_query_string() const;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
@@ -1329,7 +1329,7 @@
  *  The conversion attempts to ensure that, for any pair of values supplied
  *  to the conversion algorithm, the result of comparing the original
  *  values (with a numeric comparison operator) will be the same as the
- *  result of comparing the resulting values (with a string comparison
+ *  result of comparing the resulting values (with a std::string comparison
  *  operator).  On platforms which represent doubles with the precisions
  *  specified by IEEE_754, this will be the case: if the representation of
  *  doubles is more precise, it is possible that two very close doubles
@@ -1349,19 +1349,19 @@
     return std::string(buf, sortable_serialise_(value, buf));
 }
 
-/** Convert a string encoded using @a sortable_serialise back to a floating
+/** Convert a std::string encoded using @a sortable_serialise back to a floating
  *  point number.
  *
- *  This expects the input to be a string produced by @a sortable_serialise().
+ *  This expects the input to be a std::string produced by @a sortable_serialise().
  *  If the input is not such a string, the value returned is undefined (but
  *  no error will be thrown).
  *
  *  The result of the conversion will be exactly the value which was
- *  supplied to @a sortable_serialise() when making the string on platforms
+ *  supplied to @a sortable_serialise() when making the std::string on platforms
  *  which represent doubles with the precisions specified by IEEE_754, but
  *  may be a different (nearby) value on other platforms.
  *
- *  @param serialised	The serialised string to decode.
+ *  @param serialised	The serialised std::string to decode.
  */
 XAPIAN_VISIBILITY_DEFAULT
 double XAPIAN_NOTHROW(sortable_unserialise(const std::string & serialised));
diff -ur xapian-core-1.4.21/include/xapian/stem.h xapian-core-1.4.21/include/xapian/stem.h
--- xapian-core-1.4.21/include/xapian/stem.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/stem.h	2022-11-08 16:44:00.980513047 +0100
@@ -54,7 +54,7 @@
     /// Stem the specified word.
     virtual std::string operator()(const std::string & word) = 0;
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     virtual std::string get_description() const = 0;
 };
 
@@ -165,7 +165,7 @@
     /// Return true if this is a no-op stemmer.
     bool is_none() const { return !internal.get(); }
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** Return a list of available languages.
diff -ur xapian-core-1.4.21/include/xapian/termgenerator.h xapian-core-1.4.21/include/xapian/termgenerator.h
--- xapian-core-1.4.21/include/xapian/termgenerator.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/termgenerator.h	2022-11-08 16:44:00.972513076 +0100
@@ -268,7 +268,7 @@
      */
     void set_termpos(Xapian::termpos termpos);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 };
 
diff -ur xapian-core-1.4.21/include/xapian/termiterator.h xapian-core-1.4.21/include/xapian/termiterator.h
--- xapian-core-1.4.21/include/xapian/termiterator.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/termiterator.h	2022-11-08 16:44:01.004512962 +0100
@@ -126,7 +126,7 @@
      */
     void skip_to(const std::string &term);
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal TermIterator is what the C++ STL calls an
diff -ur xapian-core-1.4.21/include/xapian/unicode.h xapian-core-1.4.21/include/xapian/unicode.h
--- xapian-core-1.4.21/include/xapian/unicode.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/unicode.h	2022-11-08 16:44:00.992513004 +0100
@@ -58,16 +58,16 @@
     /** Return the number of bytes left in the iterator's buffer. */
     size_t left() const { return p ? end - p : 0; }
 
-    /** Assign a new string to the iterator.
+    /** Assign a new std::string to the iterator.
      *
-     *  The iterator will forget the string it was iterating through, and
-     *  return characters from the start of the new string when next called.
-     *  The string is not copied into the iterator, so it must remain valid
+     *  The iterator will forget the std::string it was iterating through, and
+     *  return characters from the start of the new std::string when next called.
+     *  The std::string is not copied into the iterator, so it must remain valid
      *  while the iteration is in progress.
      *
-     *  @param p_ A pointer to the start of the string to read.
+     *  @param p_ A pointer to the start of the std::string to read.
      *
-     *  @param len The length of the string to read.
+     *  @param len The length of the std::string to read.
      */
     void assign(const char* p_, size_t len) {
 	if (len) {
@@ -79,47 +79,47 @@
 	}
     }
 
-    /** Assign a new string to the iterator.
+    /** Assign a new std::string to the iterator.
      *
-     *  The iterator will forget the string it was iterating through, and
-     *  return characters from the start of the new string when next called.
-     *  The string is not copied into the iterator, so it must remain valid
+     *  The iterator will forget the std::string it was iterating through, and
+     *  return characters from the start of the new std::string when next called.
+     *  The std::string is not copied into the iterator, so it must remain valid
      *  while the iteration is in progress.
      *
-     *  @param s The string to read.  Must not be modified while the iteration
+     *  @param s The std::string to read.  Must not be modified while the iteration
      *		 is in progress.
      */
     void assign(const std::string& s) { assign(s.data(), s.size()); }
 
     /** Create an iterator given a pointer to a null terminated string.
      *
-     *  The iterator will return characters from the start of the string when
-     *  next called.  The string is not copied into the iterator, so it must
+     *  The iterator will return characters from the start of the std::string when
+     *  next called.  The std::string is not copied into the iterator, so it must
      *  remain valid while the iteration is in progress.
      *
-     *  @param p_ A pointer to the start of the null terminated string to read.
+     *  @param p_ A pointer to the start of the null terminated std::string to read.
      */
     explicit Utf8Iterator(const char* p_);
 
     /** Create an iterator given a pointer and a length.
      *
-     *  The iterator will return characters from the start of the string when
-     *  next called.  The string is not copied into the iterator, so it must
+     *  The iterator will return characters from the start of the std::string when
+     *  next called.  The std::string is not copied into the iterator, so it must
      *  remain valid while the iteration is in progress.
      *
-     *  @param p_ A pointer to the start of the string to read.
+     *  @param p_ A pointer to the start of the std::string to read.
      *
-     *  @param len The length of the string to read.
+     *  @param len The length of the std::string to read.
      */
     Utf8Iterator(const char* p_, size_t len) { assign(p_, len); }
 
     /** Create an iterator given a string.
      *
-     *  The iterator will return characters from the start of the string when
-     *  next called.  The string is not copied into the iterator, so it must
+     *  The iterator will return characters from the start of the std::string when
+     *  next called.  The std::string is not copied into the iterator, so it must
      *  remain valid while the iteration is in progress.
      *
-     *  @param s The string to read.  Must not be modified while the iteration
+     *  @param s The std::string to read.  Must not be modified while the iteration
      *		 is in progress.
      */
     Utf8Iterator(const std::string& s) { assign(s.data(), s.size()); }
diff -ur xapian-core-1.4.21/include/xapian/valueiterator.h xapian-core-1.4.21/include/xapian/valueiterator.h
--- xapian-core-1.4.21/include/xapian/valueiterator.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/valueiterator.h	2022-11-08 16:44:00.980513047 +0100
@@ -173,7 +173,7 @@
     bool (check)(Xapian::docid docid);
 #endif
 
-    /// Return a string describing this object.
+    /// Return a std::string describing this object.
     std::string get_description() const;
 
     /** @private @internal ValueIterator is what the C++ STL calls an
diff -ur xapian-core-1.4.21/include/xapian/version_h.cc xapian-core-1.4.21/include/xapian/version_h.cc
--- xapian-core-1.4.21/include/xapian/version_h.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/version_h.cc	2022-11-08 16:44:15.416461728 +0100
@@ -101,7 +101,7 @@
 "#define XAPIAN_ENABLE_VISIBILITY",
 "",
 #endif
-"/// The version of Xapian as a C string literal.",
+"/// The version of Xapian as a C std::string literal.",
 "#define XAPIAN_VERSION ", STRING_VERSION,
 "",
 "/** The major component of the Xapian version.",
diff -ur xapian-core-1.4.21/include/xapian/weight.h xapian-core-1.4.21/include/xapian/weight.h
--- xapian-core-1.4.21/include/xapian/weight.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian/weight.h	2022-11-08 16:44:00.984513032 +0100
@@ -212,7 +212,7 @@
      *  method in your subclass as shown here:
      *  https://trac.xapian.org/ticket/554#comment:1
      *
-     *  @param serialised	A string containing the serialised parameters.
+     *  @param serialised	A std::string containing the serialised parameters.
      */
     virtual Weight * unserialise(const std::string & serialised) const;
 
@@ -445,7 +445,7 @@
 
 /// Xapian::Weight subclass implementing the tf-idf weighting scheme.
 class XAPIAN_VISIBILITY_DEFAULT TfIdfWeight : public Weight {
-    /* Three character string indicating the normalizations for tf(wdf), idf and
+    /* Three character std::string indicating the normalizations for tf(wdf), idf and
        tfidf weight. */
     std::string normalizations;
 
@@ -465,11 +465,11 @@
   public:
     /** Construct a TfIdfWeight
      *
-     *  @param normalizations	A three character string indicating the
+     *  @param normalizations	A three character std::string indicating the
      *				normalizations to be used for the tf(wdf), idf
      *				and document weight.  (default: "ntn")
      *
-     * The @a normalizations string works like so:
+     * The @a normalizations std::string works like so:
      *
      * @li The first character specifies the normalization for the wdf.  The
      *     following normalizations are currently supported:
diff -ur xapian-core-1.4.21/include/xapian.h xapian-core-1.4.21/include/xapian.h
--- xapian-core-1.4.21/include/xapian.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/include/xapian.h	2022-11-08 16:44:00.968513089 +0100
@@ -107,7 +107,7 @@
 
 // Functions returning library version:
 
-/** Report the version string of the library which the program is linked with.
+/** Report the version std::string of the library which the program is linked with.
  *
  * This may be different to the version compiled against (given by
  * XAPIAN_VERSION) if shared libraries are being used.
diff -ur xapian-core-1.4.21/languages/compiler/header.h xapian-core-1.4.21/languages/compiler/header.h
--- xapian-core-1.4.21/languages/compiler/header.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/languages/compiler/header.h	2022-11-08 16:44:01.120512549 +0100
@@ -178,7 +178,7 @@
 
 struct amongvec {
 
-    symbol * b;      /* the string giving the case */
+    symbol * b;      /* the std::string giving the case */
     int size;        /* - and its size */
     struct node * action; /* the corresponding action */
     int i;           /* the amongvec index of the longest substring of b */
diff -ur xapian-core-1.4.21/languages/sbl-dispatch.h xapian-core-1.4.21/languages/sbl-dispatch.h
--- xapian-core-1.4.21/languages/sbl-dispatch.h	2022-09-22 07:29:21.000000000 +0200
+++ xapian-core-1.4.21/languages/sbl-dispatch.h	2022-11-08 16:44:01.132512507 +0100
@@ -1,5 +1,5 @@
 /** @file
- *  @brief Map string to language code
+ *  @brief Map std::string to language code
  */
 /* Warning: This file is generated by ./languages/collate-sbl - do not modify directly! */
 /* Copyright (C) 2007,2012,2013,2015 Olly Betts
diff -ur xapian-core-1.4.21/languages/stem.cc xapian-core-1.4.21/languages/stem.cc
--- xapian-core-1.4.21/languages/stem.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/languages/stem.cc	2022-11-08 16:44:15.648460904 +0100
@@ -146,7 +146,7 @@
 string
 Stem::get_description() const
 {
-    string desc = "Xapian::Stem(";
+    std::string desc = "Xapian::Stem(";
     if (internal.get()) {
 	desc += internal->get_description();
 	desc += ')';
diff -ur xapian-core-1.4.21/languages/steminternal.cc xapian-core-1.4.21/languages/steminternal.cc
--- xapian-core-1.4.21/languages/steminternal.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/languages/steminternal.cc	2022-11-08 16:44:15.648460904 +0100
@@ -145,7 +145,7 @@
 }
 
 string
-SnowballStemImplementation::operator()(const string & word)
+SnowballStemImplementation::operator()(const std::string & word)
 {
     const symbol * s = reinterpret_cast<const symbol *>(word.data());
     replace_s(0, l, word.size(), s);
diff -ur xapian-core-1.4.21/languages/steminternal.h xapian-core-1.4.21/languages/steminternal.h
--- xapian-core-1.4.21/languages/steminternal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/languages/steminternal.h	2022-11-08 16:44:01.116512564 +0100
@@ -36,8 +36,8 @@
 typedef int (*among_function)(Xapian::StemImplementation *);
 
 struct among {
-    int s_size;		/* length of search string (in symbols) */
-    unsigned s;		/* offset in pool to search string */
+    int s_size;		/* length of search std::string (in symbols) */
+    unsigned s;		/* offset in pool to search std::string */
     int substring_i;	/* index to longest matching substring */
     int result;		/* result of the lookup */
 };
diff -ur xapian-core-1.4.21/matcher/collapser.cc xapian-core-1.4.21/matcher/collapser.cc
--- xapian-core-1.4.21/matcher/collapser.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/collapser.cc	2022-11-08 16:44:15.588461116 +0100
@@ -74,7 +74,7 @@
 {
     ++docs_considered;
     // The postlist will supply the collapse key for a remote match.
-    const string * key_ptr = postlist->get_collapse_key();
+    const std::string * key_ptr = postlist->get_collapse_key();
     if (key_ptr) {
 	item.collapse_key = *key_ptr;
     } else {
@@ -108,7 +108,7 @@
 }
 
 Xapian::doccount
-Collapser::get_collapse_count(const string & collapse_key, int percent_cutoff,
+Collapser::get_collapse_count(const std::string & collapse_key, int percent_cutoff,
 			      double min_weight) const
 {
     auto key = table.find(collapse_key);
diff -ur xapian-core-1.4.21/matcher/exactphrasepostlist.cc xapian-core-1.4.21/matcher/exactphrasepostlist.cc
--- xapian-core-1.4.21/matcher/exactphrasepostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/exactphrasepostlist.cc	2022-11-08 16:44:15.580461145 +0100
@@ -32,8 +32,8 @@
 using namespace std;
 
 ExactPhrasePostList::ExactPhrasePostList(PostList *source_,
-					 const vector<PostList*>::const_iterator &terms_begin,
-					 const vector<PostList*>::const_iterator &terms_end)
+					 const std::vector<PostList*>::const_iterator &terms_begin,
+					 const std::vector<PostList*>::const_iterator &terms_end)
     : SelectPostList(source_), terms(terms_begin, terms_end)
 {
     size_t n = terms.size();
@@ -61,7 +61,7 @@
 }
 
 class TermCompare {
-    vector<PostList *> & terms;
+    std::vector<PostList *> & terms;
 
   public:
     explicit TermCompare(vector<PostList *> & terms_) : terms(terms_) { }
@@ -136,7 +136,7 @@
     //
     // We use the minimum wdf of a sub-postlist as our estimate.  See the
     // comment in NearPostList::get_wdf() for justification of this estimate.
-    vector<PostList *>::const_iterator i = terms.begin();
+    std::vector<PostList *>::const_iterator i = terms.begin();
     Xapian::termcount wdf = (*i)->get_wdf();
     while (++i != terms.end()) {
 	wdf = min(wdf, (*i)->get_wdf());
diff -ur xapian-core-1.4.21/matcher/externalpostlist.cc xapian-core-1.4.21/matcher/externalpostlist.cc
--- xapian-core-1.4.21/matcher/externalpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/externalpostlist.cc	2022-11-08 16:44:15.576461160 +0100
@@ -196,7 +196,7 @@
 string
 ExternalPostList::get_description() const
 {
-    string desc = "ExternalPostList(";
+    std::string desc = "ExternalPostList(";
     if (source.get()) desc += source->get_description();
     desc += ")";
     return desc;
diff -ur xapian-core-1.4.21/matcher/localsubmatch.cc xapian-core-1.4.21/matcher/localsubmatch.cc
--- xapian-core-1.4.21/matcher/localsubmatch.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/localsubmatch.cc	2022-11-08 16:44:15.572461173 +0100
@@ -111,7 +111,7 @@
 string
 LazyWeight::name() const
 {
-    string desc = "LazyWeight(";
+    std::string desc = "LazyWeight(";
     desc += real_wt->name();
     desc += ")";
     return desc;
@@ -124,7 +124,7 @@
 }
 
 LazyWeight *
-LazyWeight::unserialise(const string &) const
+LazyWeight::unserialise(const std::string &) const
 {
     throw Xapian::InvalidOperationError("LazyWeight::unserialise()");
 }
diff -ur xapian-core-1.4.21/matcher/maxpostlist.cc xapian-core-1.4.21/matcher/maxpostlist.cc
--- xapian-core-1.4.21/matcher/maxpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/maxpostlist.cc	2022-11-08 16:44:15.572461173 +0100
@@ -247,7 +247,7 @@
 string
 MaxPostList::get_description() const
 {
-    string desc("(");
+    std::string desc("(");
     desc += plist[0]->get_description();
     for (size_t i = 1; i < n_kids; ++i) {
 	desc += " MAX ";
diff -ur xapian-core-1.4.21/matcher/mergepostlist.cc xapian-core-1.4.21/matcher/mergepostlist.cc
--- xapian-core-1.4.21/matcher/mergepostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/mergepostlist.cc	2022-11-08 16:44:15.588461116 +0100
@@ -88,7 +88,7 @@
     LOGCALL(MATCH, Xapian::doccount, "MergePostList::get_termfreq_max", NO_ARGS);
     // sum of termfreqs for all children
     Xapian::doccount total = 0;
-    vector<PostList *>::const_iterator i;
+    std::vector<PostList *>::const_iterator i;
     for (i = plists.begin(); i != plists.end(); ++i) {
 	total += (*i)->get_termfreq_max();
     }
@@ -101,7 +101,7 @@
     LOGCALL(MATCH, Xapian::doccount, "MergePostList::get_termfreq_min", NO_ARGS);
     // sum of termfreqs for all children
     Xapian::doccount total = 0;
-    vector<PostList *>::const_iterator i;
+    std::vector<PostList *>::const_iterator i;
     for (i = plists.begin(); i != plists.end(); ++i) {
 	total += (*i)->get_termfreq_min();
     }
@@ -114,7 +114,7 @@
     LOGCALL(MATCH, Xapian::doccount, "MergePostList::get_termfreq_est", NO_ARGS);
     // sum of termfreqs for all children
     Xapian::doccount total = 0;
-    vector<PostList *>::const_iterator i;
+    std::vector<PostList *>::const_iterator i;
     for (i = plists.begin(); i != plists.end(); ++i) {
 	total += (*i)->get_termfreq_est();
     }
@@ -139,18 +139,18 @@
     RETURN(plists[current]->get_weight());
 }
 
-const string *
+const std::string *
 MergePostList::get_sort_key() const
 {
-    LOGCALL(MATCH, const string *, "MergePostList::get_sort_key", NO_ARGS);
+    LOGCALL(MATCH, const std::string *, "MergePostList::get_sort_key", NO_ARGS);
     Assert(current != -1);
     RETURN(plists[current]->get_sort_key());
 }
 
-const string *
+const std::string *
 MergePostList::get_collapse_key() const
 {
-    LOGCALL(MATCH, const string *, "MergePostList::get_collapse_key", NO_ARGS);
+    LOGCALL(MATCH, const std::string *, "MergePostList::get_collapse_key", NO_ARGS);
     Assert(current != -1);
     RETURN(plists[current]->get_collapse_key());
 }
@@ -167,7 +167,7 @@
 {
     LOGCALL(MATCH, double, "MergePostList::recalc_maxweight", NO_ARGS);
     w_max = 0;
-    vector<PostList *>::iterator i;
+    std::vector<PostList *>::iterator i;
     for (i = plists.begin(); i != plists.end(); ++i) {
 	double w = (*i)->recalc_maxweight();
 	if (w > w_max) w_max = w;
@@ -186,8 +186,8 @@
 string
 MergePostList::get_description() const
 {
-    string desc = "( Merge ";
-    vector<PostList *>::const_iterator i;
+    std::string desc = "( Merge ";
+    std::vector<PostList *>::const_iterator i;
     for (i = plists.begin(); i != plists.end(); ++i) {
 	desc += (*i)->get_description() + " ";
     }
diff -ur xapian-core-1.4.21/matcher/mergepostlist.h xapian-core-1.4.21/matcher/mergepostlist.h
--- xapian-core-1.4.21/matcher/mergepostlist.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/mergepostlist.h	2022-11-08 16:44:01.080512691 +0100
@@ -40,7 +40,7 @@
 
 	double w_max;
 
-	vector<PostList *> plists;
+	std::vector<PostList *> plists;
 
 	int current;
 
@@ -67,8 +67,8 @@
 
 	Xapian::docid get_docid() const;
 	double get_weight() const;
-	const string * get_sort_key() const;
-	const string * get_collapse_key() const;
+	const std::string * get_sort_key() const;
+	const std::string * get_collapse_key() const;
 
 	double get_maxweight() const;
 
@@ -78,7 +78,7 @@
 	PostList *skip_to(Xapian::docid did, double w_min);
 	bool at_end() const;
 
-	string get_description() const;
+	std::string get_description() const;
 
 	/** Return the document length of the document the current term
 	 *  comes from.
diff -ur xapian-core-1.4.21/matcher/msetpostlist.cc xapian-core-1.4.21/matcher/msetpostlist.cc
--- xapian-core-1.4.21/matcher/msetpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/msetpostlist.cc	2022-11-08 16:44:15.568461188 +0100
@@ -86,18 +86,18 @@
     RETURN(mset_internal->items[cursor].wt);
 }
 
-const string *
+const std::string *
 MSetPostList::get_sort_key() const
 {
-    LOGCALL(MATCH, const string *, "MSetPostList::get_sort_key", NO_ARGS);
+    LOGCALL(MATCH, const std::string *, "MSetPostList::get_sort_key", NO_ARGS);
     Assert(cursor != -1);
     RETURN(&mset_internal->items[cursor].sort_key);
 }
 
-const string *
+const std::string *
 MSetPostList::get_collapse_key() const
 {
-    LOGCALL(MATCH, const string *, "MSetPostList::get_collapse_key", NO_ARGS);
+    LOGCALL(MATCH, const std::string *, "MSetPostList::get_collapse_key", NO_ARGS);
     Assert(cursor != -1);
     RETURN(&mset_internal->items[cursor].collapse_key);
 }
@@ -161,7 +161,7 @@
 string
 MSetPostList::get_description() const
 {
-    string desc("(MSet ");
+    std::string desc("(MSet ");
     desc += mset_internal->get_description();
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/matcher/multiandpostlist.cc xapian-core-1.4.21/matcher/multiandpostlist.cc
--- xapian-core-1.4.21/matcher/multiandpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/multiandpostlist.cc	2022-11-08 16:44:15.588461116 +0100
@@ -251,7 +251,7 @@
 std::string
 MultiAndPostList::get_description() const
 {
-    string desc("(");
+    std::string desc("(");
     desc += plist[0]->get_description();
     for (size_t i = 1; i < n_kids; ++i) {
 	desc += " AND ";
diff -ur xapian-core-1.4.21/matcher/multimatch.cc xapian-core-1.4.21/matcher/multimatch.cc
--- xapian-core-1.4.21/matcher/multimatch.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/multimatch.cc	2022-11-08 16:44:15.584461131 +0100
@@ -172,7 +172,7 @@
 static void
 split_rset_by_db(const Xapian::RSet * rset,
 		 Xapian::doccount number_of_subdbs,
-		 vector<Xapian::RSet> & subrsets)
+		 std::vector<Xapian::RSet> & subrsets)
 {
     LOGCALL_STATIC_VOID(MATCH, "split_rset_by_db", rset | number_of_subdbs | subrsets);
     if (rset && !rset->empty()) {
@@ -225,8 +225,8 @@
 		    Xapian::Weight::Internal & stats)
 {
     LOGCALL_STATIC_VOID(MATCH, "prepare_sub_matches", leaves | stats);
-    // We use a vector<bool> to track which SubMatches we're already prepared.
-    vector<bool> prepared;
+    // We use a std::vector<bool> to track which SubMatches we're already prepared.
+    std::vector<bool> prepared;
     prepared.resize(leaves.size(), false);
     size_t unprepared = leaves.size();
     bool nowait = true;
@@ -288,7 +288,7 @@
 		       double time_limit_,
 		       Xapian::Weight::Internal & stats,
 		       const Xapian::Weight * weight_,
-		       const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_,
+		       const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_,
 		       bool have_sorter, bool have_mdecider)
 	: db(db_), query(query_),
 	  collapse_max(collapse_max_), collapse_key(collapse_key_),
@@ -306,7 +306,7 @@
     if (query.empty()) return;
 
     Xapian::doccount number_of_subdbs = db.internal.size();
-    vector<Xapian::RSet> subrsets;
+    std::vector<Xapian::RSet> subrsets;
     split_rset_by_db(omrset, number_of_subdbs, subrsets);
 
     for (size_t i = 0; i != number_of_subdbs; ++i) {
@@ -434,7 +434,7 @@
     }
 
     // Get postlists and term info
-    vector<PostList *> postlists;
+    std::vector<PostList *> postlists;
     Xapian::termcount total_subqs = 0;
     // Keep a count of matches which we know exist, but we won't see.  This
     // occurs when a submatch is remote, and returns a lower bound on the
@@ -502,7 +502,7 @@
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     unsigned greatest_wt_subqs_db_num = UINT_MAX;
 #endif
-    vector<Xapian::Internal::MSetItem> items;
+    std::vector<Xapian::Internal::MSetItem> items;
 
     // maximum weight a document could possibly have
     const double max_possible = pl->recalc_maxweight();
@@ -660,7 +660,7 @@
 	}
 
 	if (sort_by != REL) {
-	    const string * ptr = pl->get_sort_key();
+	    const std::string * ptr = pl->get_sort_key();
 	    if (ptr) {
 		new_item.sort_key = *ptr;
 	    } else if (sorter) {
@@ -763,7 +763,7 @@
 		    // Scan through (unsorted) MSet looking for entry.
 		    // FIXME: more efficient way than just scanning?
 		    Xapian::docid olddid = old_item.did;
-		    vector<Xapian::Internal::MSetItem>::iterator i;
+		    std::vector<Xapian::Internal::MSetItem>::iterator i;
 		    for (i = items.begin(); i != items.end(); ++i) {
 			if (i->did == olddid) {
 			    LOGLINE(MATCH, "collapse: removing " <<
@@ -886,7 +886,7 @@
 			items.pop_back();
 		    }
 #ifdef XAPIAN_ASSERTIONS_PARANOID
-		    vector<Xapian::Internal::MSetItem>::const_iterator i;
+		    std::vector<Xapian::Internal::MSetItem>::const_iterator i;
 		    for (i = items.begin(); i != items.end(); ++i) {
 			Assert(i->wt >= min_weight);
 		    }
@@ -932,7 +932,7 @@
 		items.pop_back();
 	    }
 #ifdef XAPIAN_ASSERTIONS_PARANOID
-	    vector<Xapian::Internal::MSetItem>::const_iterator j;
+	    std::vector<Xapian::Internal::MSetItem>::const_iterator j;
 	    for (j = items.begin(); j != items.end(); ++j) {
 		Assert(j->wt >= min_wt);
 	    }
@@ -1145,7 +1145,7 @@
 	    // unwanted elements end up at the end of items, which means
 	    // that the call to erase() to remove them doesn't have to copy
 	    // any elements.
-	    vector<Xapian::Internal::MSetItem>::reverse_iterator nth;
+	    std::vector<Xapian::Internal::MSetItem>::reverse_iterator nth;
 	    nth = items.rbegin() + first;
 	    nth_element(items.rbegin(), nth, items.rend(), mcmp);
 	    // Erase the trailing "first" elements
diff -ur xapian-core-1.4.21/matcher/multimatch.h xapian-core-1.4.21/matcher/multimatch.h
--- xapian-core-1.4.21/matcher/multimatch.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/multimatch.h	2022-11-08 16:44:01.080512691 +0100
@@ -68,10 +68,10 @@
 	bool recalculate_w_max;
 
 	/** Is each sub-database remote? */
-	vector<bool> is_remote;
+	std::vector<bool> is_remote;
 
 	/// The matchspies to use.
-	const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies;
+	const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies;
 
 	/** get the maxweight that the postlist pl may return, calling
 	 *  recalc_maxweight if recalculate_w_max is set, and unsetting it.
@@ -115,7 +115,7 @@
 		   double time_limit_,
 		   Xapian::Weight::Internal & stats,
 		   const Xapian::Weight *wtscheme,
-		   const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_,
+		   const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_,
 		   bool have_sorter, bool have_mdecider);
 
 	/** Run the match and generate an MSet object.
diff -ur xapian-core-1.4.21/matcher/multixorpostlist.cc xapian-core-1.4.21/matcher/multixorpostlist.cc
--- xapian-core-1.4.21/matcher/multixorpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/multixorpostlist.cc	2022-11-08 16:44:15.568461188 +0100
@@ -371,7 +371,7 @@
 string
 MultiXorPostList::get_description() const
 {
-    string desc("(");
+    std::string desc("(");
     desc += plist[0]->get_description();
     for (size_t i = 1; i < n_kids; ++i) {
 	desc += " XOR ";
diff -ur xapian-core-1.4.21/matcher/nearpostlist.cc xapian-core-1.4.21/matcher/nearpostlist.cc
--- xapian-core-1.4.21/matcher/nearpostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/nearpostlist.cc	2022-11-08 16:44:15.572461173 +0100
@@ -35,8 +35,8 @@
 
 NearPostList::NearPostList(PostList *source_,
 			   Xapian::termpos window_,
-			   const vector<PostList*>::const_iterator &terms_begin,
-			   const vector<PostList*>::const_iterator &terms_end)
+			   const std::vector<PostList*>::const_iterator &terms_begin,
+			   const std::vector<PostList*>::const_iterator &terms_end)
     : SelectPostList(source_), window(window_), terms(terms_begin, terms_end)
 {
     size_t n = terms.size();
@@ -189,7 +189,7 @@
     //
     // If this estimate proves to give bad results, we can revisit this and try
     // a better approximation.
-    vector<PostList *>::const_iterator i = terms.begin();
+    std::vector<PostList *>::const_iterator i = terms.begin();
     Xapian::termcount wdf = (*i)->get_wdf();
     while (++i != terms.end()) {
 	wdf = min(wdf, (*i)->get_wdf());
@@ -223,7 +223,7 @@
 string
 NearPostList::get_description() const
 {
-    string m = "(Near ";
+    std::string m = "(Near ";
     m += str(window);
     m += ' ';
     m += source->get_description();
diff -ur xapian-core-1.4.21/matcher/orpospostlist.cc xapian-core-1.4.21/matcher/orpospostlist.cc
--- xapian-core-1.4.21/matcher/orpospostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/orpospostlist.cc	2022-11-08 16:44:15.568461188 +0100
@@ -124,7 +124,7 @@
 std::string
 OrPosPostList::get_description() const
 {
-    string desc = "OrPosPostList(";
+    std::string desc = "OrPosPostList(";
     desc += pl->get_description();
     desc += ')';
     return desc;
diff -ur xapian-core-1.4.21/matcher/phrasepostlist.cc xapian-core-1.4.21/matcher/phrasepostlist.cc
--- xapian-core-1.4.21/matcher/phrasepostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/phrasepostlist.cc	2022-11-08 16:44:15.580461145 +0100
@@ -34,8 +34,8 @@
 
 PhrasePostList::PhrasePostList(PostList *source_,
 			       Xapian::termpos window_,
-			       const vector<PostList*>::const_iterator &terms_begin,
-			       const vector<PostList*>::const_iterator &terms_end)
+			       const std::vector<PostList*>::const_iterator &terms_begin,
+			       const std::vector<PostList*>::const_iterator &terms_end)
     : SelectPostList(source_), window(window_), terms(terms_begin, terms_end)
 {
     size_t n = terms.size();
@@ -93,7 +93,7 @@
     //
     // We use the minimum wdf of a sub-postlist as our estimate.  See the
     // comment in NearPostList::get_wdf() for justification of this estimate.
-    vector<PostList *>::const_iterator i = terms.begin();
+    std::vector<PostList *>::const_iterator i = terms.begin();
     Xapian::termcount wdf = (*i)->get_wdf();
     while (++i != terms.end()) {
 	wdf = min(wdf, (*i)->get_wdf());
@@ -127,7 +127,7 @@
 string
 PhrasePostList::get_description() const
 {
-    string m = "(Phrase ";
+    std::string m = "(Phrase ";
     m += str(window);
     m += ' ';
     m += source->get_description();
diff -ur xapian-core-1.4.21/matcher/remotesubmatch.cc xapian-core-1.4.21/matcher/remotesubmatch.cc
--- xapian-core-1.4.21/matcher/remotesubmatch.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/remotesubmatch.cc	2022-11-08 16:44:15.576461160 +0100
@@ -30,7 +30,7 @@
 
 RemoteSubMatch::RemoteSubMatch(RemoteDatabase *db_,
 			       bool decreasing_relevance_,
-			       const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_)
+			       const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies_)
 	: db(db_),
 	  decreasing_relevance(decreasing_relevance_),
 	  matchspies(matchspies_)
diff -ur xapian-core-1.4.21/matcher/remotesubmatch.h xapian-core-1.4.21/matcher/remotesubmatch.h
--- xapian-core-1.4.21/matcher/remotesubmatch.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/remotesubmatch.h	2022-11-08 16:44:01.092512649 +0100
@@ -54,13 +54,13 @@
     double percent_factor;
 
     /// The matchspies to use.
-    const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies;
+    const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies;
 
   public:
     /// Constructor.
     RemoteSubMatch(RemoteDatabase *db_,
 		   bool decreasing_relevance_,
-		   const vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
+		   const std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> & matchspies);
 
     /// Fetch and collate statistics.
     bool prepare_match(bool nowait, Xapian::Weight::Internal & total_stats);
diff -ur xapian-core-1.4.21/matcher/valuegepostlist.cc xapian-core-1.4.21/matcher/valuegepostlist.cc
--- xapian-core-1.4.21/matcher/valuegepostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/valuegepostlist.cc	2022-11-08 16:44:15.576461160 +0100
@@ -37,7 +37,7 @@
     if (!valuelist) valuelist = db->open_value_list(slot);
     valuelist->next();
     while (!valuelist->at_end()) {
-	const string & v = valuelist->get_value();
+	const std::string & v = valuelist->get_value();
 	if (v >= begin) return NULL;
 	valuelist->next();
     }
@@ -52,7 +52,7 @@
     if (!valuelist) valuelist = db->open_value_list(slot);
     valuelist->skip_to(did);
     while (!valuelist->at_end()) {
-	const string & v = valuelist->get_value();
+	const std::string & v = valuelist->get_value();
 	if (v >= begin) return NULL;
 	valuelist->next();
     }
@@ -70,7 +70,7 @@
     if (!valid) {
 	return NULL;
     }
-    const string & v = valuelist->get_value();
+    const std::string & v = valuelist->get_value();
     valid = (v >= begin);
     return NULL;
 }
@@ -78,7 +78,7 @@
 string
 ValueGePostList::get_description() const
 {
-    string desc = "ValueGePostList(";
+    std::string desc = "ValueGePostList(";
     desc += str(slot);
     desc += ", ";
     description_append(desc, begin);
diff -ur xapian-core-1.4.21/matcher/valuerangepostlist.cc xapian-core-1.4.21/matcher/valuerangepostlist.cc
--- xapian-core-1.4.21/matcher/valuerangepostlist.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/valuerangepostlist.cc	2022-11-08 16:44:15.572461173 +0100
@@ -54,7 +54,7 @@
 }
 
 static double
-string_frac(const string &s, size_t prefix)
+string_frac(const std::string &s, size_t prefix)
 {
     double r = 0;
     double f = 1.0;
@@ -203,7 +203,7 @@
     if (!valuelist) valuelist = db->open_value_list(slot);
     valuelist->next();
     while (!valuelist->at_end()) {
-	const string & v = valuelist->get_value();
+	const std::string & v = valuelist->get_value();
 	if (v >= begin && v <= end) {
 	    return NULL;
 	}
@@ -220,7 +220,7 @@
     if (!valuelist) valuelist = db->open_value_list(slot);
     valuelist->skip_to(did);
     while (!valuelist->at_end()) {
-	const string & v = valuelist->get_value();
+	const std::string & v = valuelist->get_value();
 	if (v >= begin && v <= end) {
 	    return NULL;
 	}
@@ -240,7 +240,7 @@
     if (!valid) {
 	return NULL;
     }
-    const string & v = valuelist->get_value();
+    const std::string & v = valuelist->get_value();
     valid = (v >= begin && v <= end);
     return NULL;
 }
@@ -260,7 +260,7 @@
 string
 ValueRangePostList::get_description() const
 {
-    string desc = "ValueRangePostList(";
+    std::string desc = "ValueRangePostList(";
     desc += str(slot);
     desc += ", ";
     description_append(desc, begin);
diff -ur xapian-core-1.4.21/matcher/valuestreamdocument.cc xapian-core-1.4.21/matcher/valuestreamdocument.cc
--- xapian-core-1.4.21/matcher/valuestreamdocument.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/matcher/valuestreamdocument.cc	2022-11-08 16:44:15.584461131 +0100
@@ -26,9 +26,9 @@
 using namespace std;
 
 static void
-clear_valuelists(map<Xapian::valueno, ValueList *> & valuelists)
+clear_valuelists(std::map<Xapian::valueno, ValueList *> & valuelists)
 {
-    map<Xapian::valueno, ValueList *>::const_iterator i;
+    std::map<Xapian::valueno, ValueList *>::const_iterator i;
     for (i = valuelists.begin(); i != valuelists.end(); ++i) {
 	delete i->second;
     }
@@ -60,7 +60,7 @@
     }
 #endif
 
-    pair<map<Xapian::valueno, ValueList *>::iterator, bool> ret;
+    std::pair<map<Xapian::valueno, ValueList *>::iterator, bool> ret;
     ret = valuelists.insert(make_pair(slot, static_cast<ValueList*>(NULL)));
     ValueList * vl;
     if (ret.second) {
@@ -81,7 +81,7 @@
 	    ret.first->second = NULL;
 	} else if (vl->get_docid() == did) {
 	    Assert(vl);
-	    string v = vl->get_value();
+	    std::string v = vl->get_value();
 	    AssertEq(v, doc->get_value(slot));
 	    return v;
 	}
@@ -91,7 +91,7 @@
 }
 
 void
-ValueStreamDocument::do_get_all_values(map<Xapian::valueno, string> & v) const
+ValueStreamDocument::do_get_all_values(std::map<Xapian::valueno, string> & v) const
 {
     if (!doc) {
 	doc = database->open_document(did, true);
diff -ur xapian-core-1.4.21/net/progclient.cc xapian-core-1.4.21/net/progclient.cc
--- xapian-core-1.4.21/net/progclient.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/progclient.cc	2022-11-08 16:44:15.600461075 +0100
@@ -46,11 +46,11 @@
 using namespace std;
 
 #ifndef __WIN32__
-/** Split a string into a vector of strings, using a given separator
+/** Split a std::string into a vector of strings, using a given separator
  *  character (default space)
  */
 static void
-split_words(const string &text, vector<string> &words, char ws = ' ')
+split_words(const std::string &text, std::vector<string> &words, char ws = ' ')
 {
     size_t i = 0;
     if (i < text.length() && text[0] == ws) {
@@ -64,7 +64,7 @@
 }
 #endif
 
-ProgClient::ProgClient(const string &progname, const string &args,
+ProgClient::ProgClient(const std::string &progname, const std::string &args,
 		       double timeout_, bool writable, int flags)
 	: RemoteDatabase(run_program(progname, args, child),
 			 timeout_, get_progcontext(progname, args), writable,
@@ -74,14 +74,14 @@
 }
 
 string
-ProgClient::get_progcontext(const string &progname, const string &args)
+ProgClient::get_progcontext(const std::string &progname, const std::string &args)
 {
     LOGCALL_STATIC(DB, string, "ProgClient::get_progcontext", progname | args);
     RETURN("remote:prog(" + progname + " " + args + ")");
 }
 
 int
-ProgClient::run_program(const string &progname, const string &args,
+ProgClient::run_program(const std::string &progname, const std::string &args,
 #ifndef __WIN32__
 			pid_t& child
 #else
@@ -154,7 +154,7 @@
 	::close(stderrfd);
     }
 
-    vector<string> argvec;
+    std::vector<string> argvec;
     split_words(args, argvec);
 
     // We never explicitly free this memory, but that's OK as we're about
@@ -227,7 +227,7 @@
     startupinfo.dwFlags |= STARTF_USESTDHANDLES;
 
     // For some reason Windows wants a modifiable command line!
-    string cmdline = progname + ' ' + args;
+    std::string cmdline = progname + ' ' + args;
     BOOL ok = CreateProcess(0, &cmdline[0], 0, 0, TRUE, 0, 0, 0,
 			    &startupinfo, &procinfo);
     if (!ok) {
diff -ur xapian-core-1.4.21/net/progclient.h xapian-core-1.4.21/net/progclient.h
--- xapian-core-1.4.21/net/progclient.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/progclient.h	2022-11-08 16:44:01.104512606 +0100
@@ -68,7 +68,7 @@
 #endif
 			   );
 
-    /** Generate context string for Xapian::Error exception objects.
+    /** Generate context std::string for Xapian::Error exception objects.
      *
      *  @param progname	The program used to create the connection.
      *  @param args	Any arguments to the program.
diff -ur xapian-core-1.4.21/net/remoteconnection.cc xapian-core-1.4.21/net/remoteconnection.cc
--- xapian-core-1.4.21/net/remoteconnection.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/remoteconnection.cc	2022-11-08 16:44:15.600461075 +0100
@@ -88,7 +88,7 @@
 #endif
 
 RemoteConnection::RemoteConnection(int fdin_, int fdout_,
-				   const string & context_)
+				   const std::string & context_)
     : fdin(fdin_), fdout(fdout_), context(context_)
 {
 #ifdef __WIN32__
@@ -268,20 +268,20 @@
 }
 
 void
-RemoteConnection::send_message(char type, const string &message,
+RemoteConnection::send_message(char type, const std::string &message,
 			       double end_time)
 {
     LOGCALL_VOID(REMOTE, "RemoteConnection::send_message", type | message | end_time);
     if (fdout == -1)
 	throw_database_closed();
 
-    string header;
+    std::string header;
     header += type;
     header += encode_length(message.size());
 
 #ifdef __WIN32__
     HANDLE hout = fd_to_handle(fdout);
-    const string * str = &header;
+    const std::string * str = &header;
 
     size_t count = 0;
     while (true) {
@@ -322,7 +322,7 @@
 				   context, errno);
     }
 
-    const string * str = &header;
+    const std::string * str = &header;
 
     size_t count = 0;
     while (true) {
@@ -411,7 +411,7 @@
     buf[0] = type;
     size_t c = 1;
     {
-	string enc_size = encode_length(size);
+	std::string enc_size = encode_length(size);
 	c += enc_size.size();
 	// An encoded length should be just a few bytes.
 	AssertRel(c, <=, sizeof(buf));
@@ -696,7 +696,7 @@
 }
 
 int
-RemoteConnection::receive_file(const string &file, double end_time)
+RemoteConnection::receive_file(const std::string &file, double end_time)
 {
     LOGCALL(REMOTE, int, "RemoteConnection::receive_file", file | end_time);
     if (fdin == -1)
diff -ur xapian-core-1.4.21/net/remoteserver.cc xapian-core-1.4.21/net/remoteserver.cc
--- xapian-core-1.4.21/net/remoteserver.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/remoteserver.cc	2022-11-08 16:44:15.600461075 +0100
@@ -78,7 +78,7 @@
 	context = dbpaths[0];
 
 	if (!writable) {
-	    vector<std::string>::const_iterator i(dbpaths.begin());
+	    std::vector<std::string>::const_iterator i(dbpaths.begin());
 	    for (++i; i != dbpaths.end(); ++i) {
 		db->add_database(Xapian::Database(*i));
 		context += ' ';
@@ -112,7 +112,7 @@
 }
 
 message_type
-RemoteServer::get_message(double timeout, string & result,
+RemoteServer::get_message(double timeout, std::string & result,
 			  message_type required_type)
 {
     double end_time = RealTime::end_time(timeout);
@@ -126,12 +126,12 @@
     if (type < 0)
 	throw Xapian::NetworkError("Connection closed unexpectedly");
     if (type >= MSG_MAX) {
-	string errmsg("Invalid message type ");
+	std::string errmsg("Invalid message type ");
 	errmsg += str(type);
 	throw Xapian::NetworkError(errmsg);
     }
     if (required_type != MSG_MAX && type != int(required_type)) {
-	string errmsg("Expecting message type ");
+	std::string errmsg("Expecting message type ");
 	errmsg += str(int(required_type));
 	errmsg += ", got ";
 	errmsg += str(type);
@@ -141,14 +141,14 @@
 }
 
 void
-RemoteServer::send_message(reply_type type, const string &message)
+RemoteServer::send_message(reply_type type, const std::string &message)
 {
     double end_time = RealTime::end_time(active_timeout);
     unsigned char type_as_char = static_cast<unsigned char>(type);
     RemoteConnection::send_message(type_as_char, message, end_time);
 }
 
-typedef void (RemoteServer::* dispatch_func)(const string &);
+typedef void (RemoteServer::* dispatch_func)(const std::string &);
 
 void
 RemoteServer::run()
@@ -199,10 +199,10 @@
 		&RemoteServer::msg_addspelling,
 	    };
 
-	    string message;
+	    std::string message;
 	    size_t type = get_message(idle_timeout, message);
 	    if (type >= sizeof(dispatch) / sizeof(dispatch[0]) || !dispatch[type]) {
-		string errmsg("Unexpected message type ");
+		std::string errmsg("Unexpected message type ");
 		errmsg += str(type);
 		throw Xapian::InvalidArgumentError(errmsg);
 	    }
@@ -242,17 +242,17 @@
 }
 
 void
-RemoteServer::msg_allterms(const string &message)
+RemoteServer::msg_allterms(const std::string &message)
 {
-    string prev = message;
-    string reply;
+    std::string prev = message;
+    std::string reply;
 
-    const string & prefix = message;
+    const std::string & prefix = message;
     const Xapian::TermIterator end = db->allterms_end(prefix);
     for (Xapian::TermIterator t = db->allterms_begin(prefix); t != end; ++t) {
 	if (rare(prev.size() > 255))
 	    prev.resize(255);
-	const string & v = *t;
+	const std::string & v = *t;
 	size_t reuse = common_prefix_length(prev, v);
 	reply = encode_length(t.get_termfreq());
 	reply.append(1, char(reuse));
@@ -265,7 +265,7 @@
 }
 
 void
-RemoteServer::msg_termlist(const string &message)
+RemoteServer::msg_termlist(const std::string &message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
@@ -273,14 +273,14 @@
     decode_length(&p, p_end, did);
 
     send_message(REPLY_DOCLENGTH, encode_length(db->get_doclength(did)));
-    string prev;
+    std::string prev;
     const Xapian::TermIterator end = db->termlist_end(did);
     for (Xapian::TermIterator t = db->termlist_begin(did); t != end; ++t) {
 	if (rare(prev.size() > 255))
 	    prev.resize(255);
-	const string & v = *t;
+	const std::string & v = *t;
 	size_t reuse = common_prefix_length(prev, v);
-	string reply = encode_length(t.get_wdf());
+	std::string reply = encode_length(t.get_wdf());
 	reply += encode_length(t.get_termfreq());
 	reply.append(1, char(reuse));
 	reply.append(v, reuse, string::npos);
@@ -292,13 +292,13 @@
 }
 
 void
-RemoteServer::msg_positionlist(const string &message)
+RemoteServer::msg_positionlist(const std::string &message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
     Xapian::docid did;
     decode_length(&p, p_end, did);
-    string term(p, p_end - p);
+    std::string term(p, p_end - p);
 
     Xapian::termpos lastpos = static_cast<Xapian::termpos>(-1);
     const Xapian::PositionIterator end = db->positionlist_end(did, term);
@@ -313,9 +313,9 @@
 }
 
 void
-RemoteServer::msg_postlist(const string &message)
+RemoteServer::msg_postlist(const std::string &message)
 {
-    const string & term = message;
+    const std::string & term = message;
 
     Xapian::doccount termfreq = db->get_termfreq(term);
     Xapian::termcount collfreq = db->get_collection_freq(term);
@@ -327,7 +327,7 @@
 	 i != end; ++i) {
 
 	Xapian::docid newdocid = *i;
-	string reply = encode_length(newdocid - lastdocid - 1);
+	std::string reply = encode_length(newdocid - lastdocid - 1);
 	reply += encode_length(i.get_wdf());
 
 	send_message(REPLY_POSTLISTITEM, reply);
@@ -338,7 +338,7 @@
 }
 
 void
-RemoteServer::msg_writeaccess(const string & msg)
+RemoteServer::msg_writeaccess(const std::string & msg)
 {
     if (!writable)
 	throw_read_only();
@@ -362,7 +362,7 @@
 }
 
 void
-RemoteServer::msg_reopen(const string & msg)
+RemoteServer::msg_reopen(const std::string & msg)
 {
     if (!db->reopen()) {
 	send_message(REPLY_DONE, string());
@@ -372,13 +372,13 @@
 }
 
 void
-RemoteServer::msg_update(const string &)
+RemoteServer::msg_update(const std::string &)
 {
     static const char protocol[2] = {
 	char(XAPIAN_REMOTE_PROTOCOL_MAJOR_VERSION),
 	char(XAPIAN_REMOTE_PROTOCOL_MINOR_VERSION)
     };
-    string message(protocol, 2);
+    std::string message(protocol, 2);
     Xapian::doccount num_docs = db->get_doccount();
     message += encode_length(num_docs);
     message += encode_length(db->get_lastdocid() - num_docs);
@@ -387,13 +387,13 @@
     message += encode_length(db->get_doclength_upper_bound() - doclen_lb);
     message += (db->has_positions() ? '1' : '0');
     message += encode_length(db->get_total_length());
-    string uuid = db->get_uuid();
+    std::string uuid = db->get_uuid();
     message += uuid;
     send_message(REPLY_UPDATE, message);
 }
 
 void
-RemoteServer::msg_query(const string &message_in)
+RemoteServer::msg_query(const std::string &message_in)
 {
     const char *p = message_in.c_str();
     const char *p_end = p + message_in.size();
@@ -449,7 +449,7 @@
 
     // Unserialise the Weight object.
     decode_length_and_check(&p, p_end, len);
-    string wtname(p, len);
+    std::string wtname(p, len);
     p += len;
 
     const Xapian::Weight * wttype = reg.get_weighting_scheme(wtname);
@@ -471,10 +471,10 @@
     p += len;
 
     // Unserialise any MatchSpy objects.
-    vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> matchspies;
+    std::vector<Xapian::Internal::opt_intrusive_ptr<Xapian::MatchSpy>> matchspies;
     while (p != p_end) {
 	decode_length_and_check(&p, p_end, len);
-	string spytype(p, len);
+	std::string spytype(p, len);
 	const Xapian::MatchSpy * spyclass = reg.get_match_spy(spytype);
 	if (spyclass == NULL) {
 	    throw Xapian::InvalidArgumentError("Match spy " + spytype +
@@ -495,7 +495,7 @@
 
     send_message(REPLY_STATS, serialise_stats(local_stats));
 
-    string message;
+    std::string message;
     get_message(active_timeout, message, MSG_GETMSET);
     p = message.c_str();
     p_end = p + message.size();
@@ -518,7 +518,7 @@
 
     message.resize(0);
     for (auto i : matchspies) {
-	string spy_results = i->serialise_results();
+	std::string spy_results = i->serialise_results();
 	message += encode_length(spy_results.size());
 	message += spy_results;
     }
@@ -527,7 +527,7 @@
 }
 
 void
-RemoteServer::msg_document(const string &message)
+RemoteServer::msg_document(const std::string &message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
@@ -540,7 +540,7 @@
 
     Xapian::ValueIterator i;
     for (i = doc.values_begin(); i != doc.values_end(); ++i) {
-	string item = encode_length(i.get_valueno());
+	std::string item = encode_length(i.get_valueno());
 	item += *i;
 	send_message(REPLY_VALUE, item);
     }
@@ -548,7 +548,7 @@
 }
 
 void
-RemoteServer::msg_keepalive(const string &)
+RemoteServer::msg_keepalive(const std::string &)
 {
     // Ensure *our* database stays alive, as it may contain remote databases!
     db->keep_alive();
@@ -556,42 +556,42 @@
 }
 
 void
-RemoteServer::msg_termexists(const string &term)
+RemoteServer::msg_termexists(const std::string &term)
 {
     send_message((db->term_exists(term) ? REPLY_TERMEXISTS : REPLY_TERMDOESNTEXIST), string());
 }
 
 void
-RemoteServer::msg_collfreq(const string &term)
+RemoteServer::msg_collfreq(const std::string &term)
 {
     send_message(REPLY_COLLFREQ, encode_length(db->get_collection_freq(term)));
 }
 
 void
-RemoteServer::msg_termfreq(const string &term)
+RemoteServer::msg_termfreq(const std::string &term)
 {
     send_message(REPLY_TERMFREQ, encode_length(db->get_termfreq(term)));
 }
 
 void
-RemoteServer::msg_freqs(const string &term)
+RemoteServer::msg_freqs(const std::string &term)
 {
-    string msg = encode_length(db->get_termfreq(term));
+    std::string msg = encode_length(db->get_termfreq(term));
     msg += encode_length(db->get_collection_freq(term));
     send_message(REPLY_FREQS, msg);
 }
 
 void
-RemoteServer::msg_valuestats(const string & message)
+RemoteServer::msg_valuestats(const std::string & message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
     while (p != p_end) {
 	Xapian::valueno slot;
 	decode_length(&p, p_end, slot);
-	string message_out;
+	std::string message_out;
 	message_out += encode_length(db->get_value_freq(slot));
-	string bound = db->get_value_lower_bound(slot);
+	std::string bound = db->get_value_lower_bound(slot);
 	message_out += encode_length(bound.size());
 	message_out += bound;
 	bound = db->get_value_upper_bound(slot);
@@ -603,7 +603,7 @@
 }
 
 void
-RemoteServer::msg_doclength(const string &message)
+RemoteServer::msg_doclength(const std::string &message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
@@ -613,7 +613,7 @@
 }
 
 void
-RemoteServer::msg_uniqueterms(const string &message)
+RemoteServer::msg_uniqueterms(const std::string &message)
 {
     const char *p = message.data();
     const char *p_end = p + message.size();
@@ -623,7 +623,7 @@
 }
 
 void
-RemoteServer::msg_commit(const string &)
+RemoteServer::msg_commit(const std::string &)
 {
     if (!wdb)
 	throw_read_only();
@@ -634,14 +634,14 @@
 }
 
 void
-RemoteServer::msg_cancel(const string &message)
+RemoteServer::msg_cancel(const std::string &message)
 {
     msg_cancel_(message);
     send_message(REPLY_DONE, string());
 }
 
 void
-RemoteServer::msg_cancel_(const string &)
+RemoteServer::msg_cancel_(const std::string &)
 {
     if (!wdb)
 	throw_read_only();
@@ -653,7 +653,7 @@
 }
 
 void
-RemoteServer::msg_adddocument(const string & message)
+RemoteServer::msg_adddocument(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -664,7 +664,7 @@
 }
 
 void
-RemoteServer::msg_deletedocument(const string & message)
+RemoteServer::msg_deletedocument(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -680,14 +680,14 @@
 }
 
 void
-RemoteServer::msg_deletedocumentterm(const string & message)
+RemoteServer::msg_deletedocumentterm(const std::string & message)
 {
     msg_deletedocumentterm_(message);
     send_message(REPLY_DONE, string());
 }
 
 void
-RemoteServer::msg_deletedocumentterm_(const string & message)
+RemoteServer::msg_deletedocumentterm_(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -696,14 +696,14 @@
 }
 
 void
-RemoteServer::msg_replacedocument(const string & message)
+RemoteServer::msg_replacedocument(const std::string & message)
 {
     msg_replacedocument_(message);
     send_message(REPLY_DONE, string());
 }
 
 void
-RemoteServer::msg_replacedocument_(const string & message)
+RemoteServer::msg_replacedocument_(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -717,7 +717,7 @@
 }
 
 void
-RemoteServer::msg_replacedocumentterm(const string & message)
+RemoteServer::msg_replacedocumentterm(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -726,7 +726,7 @@
     const char *p_end = p + message.size();
     size_t len;
     decode_length_and_check(&p, p_end, len);
-    string unique_term(p, len);
+    std::string unique_term(p, len);
     p += len;
 
     Xapian::docid did = wdb->replace_document(unique_term, unserialise_document(string(p, p_end)));
@@ -735,24 +735,24 @@
 }
 
 void
-RemoteServer::msg_getmetadata(const string & message)
+RemoteServer::msg_getmetadata(const std::string & message)
 {
     send_message(REPLY_METADATA, db->get_metadata(message));
 }
 
 void
-RemoteServer::msg_openmetadatakeylist(const string & message)
+RemoteServer::msg_openmetadatakeylist(const std::string & message)
 {
-    string prev = message;
-    string reply;
+    std::string prev = message;
+    std::string reply;
 
-    const string & prefix = message;
+    const std::string & prefix = message;
     const Xapian::TermIterator end = db->metadata_keys_end(prefix);
     Xapian::TermIterator t = db->metadata_keys_begin(prefix);
     for (; t != end; ++t) {
 	if (rare(prev.size() > 255))
 	    prev.resize(255);
-	const string & v = *t;
+	const std::string & v = *t;
 	size_t reuse = common_prefix_length(prev, v);
 	reply.assign(1, char(reuse));
 	reply.append(v, reuse, string::npos);
@@ -763,14 +763,14 @@
 }
 
 void
-RemoteServer::msg_setmetadata(const string & message)
+RemoteServer::msg_setmetadata(const std::string & message)
 {
     msg_setmetadata_(message);
     send_message(REPLY_DONE, string());
 }
 
 void
-RemoteServer::msg_setmetadata_(const string & message)
+RemoteServer::msg_setmetadata_(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -778,21 +778,21 @@
     const char *p_end = p + message.size();
     size_t keylen;
     decode_length_and_check(&p, p_end, keylen);
-    string key(p, keylen);
+    std::string key(p, keylen);
     p += keylen;
-    string val(p, p_end - p);
+    std::string val(p, p_end - p);
     wdb->set_metadata(key, val);
 }
 
 void
-RemoteServer::msg_addspelling(const string & message)
+RemoteServer::msg_addspelling(const std::string & message)
 {
     msg_addspelling_(message);
     send_message(REPLY_DONE, string());
 }
 
 void
-RemoteServer::msg_addspelling_(const string & message)
+RemoteServer::msg_addspelling_(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
@@ -804,7 +804,7 @@
 }
 
 void
-RemoteServer::msg_removespelling(const string & message)
+RemoteServer::msg_removespelling(const std::string & message)
 {
     if (!wdb)
 	throw_read_only();
diff -ur xapian-core-1.4.21/net/remotetcpclient.cc xapian-core-1.4.21/net/remotetcpclient.cc
--- xapian-core-1.4.21/net/remotetcpclient.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/remotetcpclient.cc	2022-11-08 16:44:15.596461088 +0100
@@ -30,7 +30,7 @@
 using namespace std;
 
 int
-RemoteTcpClient::open_socket(const string & hostname, int port,
+RemoteTcpClient::open_socket(const std::string & hostname, int port,
 			     double timeout_connect)
 {
     // If TcpClient::open_socket() throws, fill in the context.
@@ -46,9 +46,9 @@
 }
 
 string
-RemoteTcpClient::get_tcpcontext(const string & hostname, int port)
+RemoteTcpClient::get_tcpcontext(const std::string & hostname, int port)
 {
-    string result("remote:tcp(");
+    std::string result("remote:tcp(");
     result += hostname;
     result += ':';
     result += str(port);
diff -ur xapian-core-1.4.21/net/remotetcpclient.h xapian-core-1.4.21/net/remotetcpclient.h
--- xapian-core-1.4.21/net/remotetcpclient.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/remotetcpclient.h	2022-11-08 16:44:01.100512621 +0100
@@ -53,7 +53,7 @@
     static int open_socket(const std::string & hostname, int port,
 			   double timeout_connect);
 
-    /** Get a context string for use when constructing Xapian::NetworkError.
+    /** Get a context std::string for use when constructing Xapian::NetworkError.
      *
      *  Note: this method is used from constructors so has been made static to
      *  avoid problems with trying to use uninitialised member variables.  In
diff -ur xapian-core-1.4.21/net/remotetcpserver.cc xapian-core-1.4.21/net/remotetcpserver.cc
--- xapian-core-1.4.21/net/remotetcpserver.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/remotetcpserver.cc	2022-11-08 16:44:15.604461060 +0100
@@ -34,7 +34,7 @@
 using namespace std;
 
 /// The RemoteTcpServer constructor, taking a database and a listening port.
-RemoteTcpServer::RemoteTcpServer(const vector<std::string> &dbpaths_,
+RemoteTcpServer::RemoteTcpServer(const std::vector<std::string> &dbpaths_,
 				 const std::string & host, int port,
 				 double active_timeout_, double idle_timeout_,
 				 bool writable_, bool verbose_)
diff -ur xapian-core-1.4.21/net/replicatetcpclient.cc xapian-core-1.4.21/net/replicatetcpclient.cc
--- xapian-core-1.4.21/net/replicatetcpclient.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/replicatetcpclient.cc	2022-11-08 16:44:15.596461088 +0100
@@ -29,7 +29,7 @@
 
 using namespace std;
 
-ReplicateTcpClient::ReplicateTcpClient(const string & hostname, int port,
+ReplicateTcpClient::ReplicateTcpClient(const std::string & hostname, int port,
 				       double timeout_connect,
 				       double socket_timeout)
     : socket(open_socket(hostname, port, timeout_connect)),
@@ -39,7 +39,7 @@
 }
 
 int
-ReplicateTcpClient::open_socket(const string & hostname, int port,
+ReplicateTcpClient::open_socket(const std::string & hostname, int port,
 				double timeout_connect)
 {
     return TcpClient::open_socket(hostname, port, timeout_connect, false);
diff -ur xapian-core-1.4.21/net/replicatetcpserver.cc xapian-core-1.4.21/net/replicatetcpserver.cc
--- xapian-core-1.4.21/net/replicatetcpserver.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/replicatetcpserver.cc	2022-11-08 16:44:15.600461075 +0100
@@ -28,8 +28,8 @@
 
 using namespace std;
 
-ReplicateTcpServer::ReplicateTcpServer(const string & host, int port,
-				       const string & path_)
+ReplicateTcpServer::ReplicateTcpServer(const std::string & host, int port,
+				       const std::string & path_)
     : TcpServer(host, port, false, false), path(path_)
 {
 }
@@ -43,13 +43,13 @@
     RemoteConnection client(socket, -1);
     try {
 	// Read start_revision from the client.
-	string start_revision;
+	std::string start_revision;
 	if (client.get_message(start_revision, 0.0) != 'R') {
 	    throw Xapian::NetworkError("Bad replication client message");
 	}
 
 	// Read dbname from the client.
-	string dbname;
+	std::string dbname;
 	if (client.get_message(dbname, 0.0) != 'D') {
 	    throw Xapian::NetworkError("Bad replication client message (2)");
 	}
@@ -57,7 +57,7 @@
 	    throw Xapian::NetworkError("dbname contained '..'");
 	}
 
-	string dbpath(path);
+	std::string dbpath(path);
 	dbpath += '/';
 	dbpath += dbname;
 	Xapian::DatabaseMaster master(dbpath);
diff -ur xapian-core-1.4.21/net/resolver.h xapian-core-1.4.21/net/resolver.h
--- xapian-core-1.4.21/net/resolver.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/resolver.h	2022-11-08 16:44:01.096512634 +0100
@@ -27,7 +27,7 @@
 #include "str.h"
 #include "xapian/error.h"
 
-using namespace std;
+using std::string;
 
 class Resolver {
     struct addrinfo* result = NULL;
diff -ur xapian-core-1.4.21/net/serialise.cc xapian-core-1.4.21/net/serialise.cc
--- xapian-core-1.4.21/net/serialise.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/serialise.cc	2022-11-08 16:44:15.596461088 +0100
@@ -41,7 +41,7 @@
 string
 serialise_stats(const Xapian::Weight::Internal &stats)
 {
-    string result;
+    std::string result;
 
     result += encode_length(stats.total_length);
     result += encode_length(stats.collection_size);
@@ -52,7 +52,7 @@
     result += static_cast<char>(stats.have_max_part);
 
     result += encode_length(stats.termfreqs.size());
-    map<string, TermFreqs>::const_iterator i;
+    std::map<string, TermFreqs>::const_iterator i;
     for (i = stats.termfreqs.begin(); i != stats.termfreqs.end(); ++i) {
 	result += encode_length(i->first.size());
 	result += i->first;
@@ -86,7 +86,7 @@
     while (n--) {
 	size_t len;
 	decode_length_and_check(&p, p_end, len);
-	string term(p, len);
+	std::string term(p, len);
 	p += len;
 	Xapian::doccount termfreq;
 	decode_length(&p, p_end, termfreq);
@@ -112,7 +112,7 @@
 string
 serialise_mset(const Xapian::MSet &mset)
 {
-    string result;
+    std::string result;
 
     result += encode_length(mset.get_firstitem());
     // Send back the raw matches_* values.  MSet::get_matches_estimated()
@@ -172,7 +172,7 @@
 
     double percent_factor = unserialise_double(&p, p_end);
 
-    vector<Xapian::Internal::MSetItem> items;
+    std::vector<Xapian::Internal::MSetItem> items;
     size_t msize;
     decode_length(&p, p_end, msize);
     while (msize-- > 0) {
@@ -181,10 +181,10 @@
 	decode_length(&p, p_end, did);
 	size_t len;
 	decode_length_and_check(&p, p_end, len);
-	string sort_key(p, len);
+	std::string sort_key(p, len);
 	p += len;
 	decode_length_and_check(&p, p_end, len);
-	string key(p, len);
+	std::string key(p, len);
 	p += len;
 	Xapian::doccount collapse_cnt;
 	decode_length(&p, p_end, collapse_cnt);
@@ -216,7 +216,7 @@
 string
 serialise_rset(const Xapian::RSet &rset)
 {
-    string result;
+    std::string result;
     const set<Xapian::docid> & items = rset.internal->get_items();
     set<Xapian::docid>::const_iterator i;
     Xapian::docid lastdid = 0;
@@ -229,7 +229,7 @@
 }
 
 Xapian::RSet
-unserialise_rset(const string &s)
+unserialise_rset(const std::string &s)
 {
     Xapian::RSet rset;
 
@@ -250,7 +250,7 @@
 string
 serialise_document(const Xapian::Document &doc)
 {
-    string result;
+    std::string result;
 
     size_t n = doc.values_count();
     result += encode_length(n);
@@ -277,7 +277,7 @@
 	Xapian::termpos oldpos = 0;
 	for (pos = term.positionlist_begin(); pos != term.positionlist_end(); ++pos) {
 	    Xapian::termpos diff = *pos - oldpos;
-	    string delta = encode_length(diff);
+	    std::string delta = encode_length(diff);
 	    result += delta;
 	    oldpos = *pos;
 	    --x;
@@ -292,7 +292,7 @@
 }
 
 Xapian::Document
-unserialise_document(const string &s)
+unserialise_document(const std::string &s)
 {
     Xapian::Document doc;
     const char * p = s.data();
@@ -314,7 +314,7 @@
     while (n_terms--) {
 	size_t len;
 	decode_length_and_check(&p, p_end, len);
-	string term(p, len);
+	std::string term(p, len);
 	p += len;
 
 	// Set all the wdf using add_term, then pass wdf_inc 0 to add_posting.
diff -ur xapian-core-1.4.21/net/serialise-error.cc xapian-core-1.4.21/net/serialise-error.cc
--- xapian-core-1.4.21/net/serialise-error.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/serialise-error.cc	2022-11-08 16:44:15.604461060 +0100
@@ -33,7 +33,7 @@
 serialise_error(const Xapian::Error &e)
 {
     // The byte before the type name is the type code.
-    string result(1, (e.get_type())[-1]);
+    std::string result(1, (e.get_type())[-1]);
     result += encode_length(e.get_context().length());
     result += e.get_context();
     result += encode_length(e.get_msg().length());
@@ -45,10 +45,10 @@
 }
 
 void
-unserialise_error(const string &serialised_error, const string &prefix,
-		  const string &new_context)
+unserialise_error(const std::string &serialised_error, const std::string &prefix,
+		  const std::string &new_context)
 {
-    // Use c_str() so last string is nul-terminated.
+    // Use c_str() so last std::string is nul-terminated.
     const char * p = serialised_error.c_str();
     const char * end = p + serialised_error.size();
     if (p != end) {
@@ -56,11 +56,11 @@
 
 	size_t len;
 	decode_length_and_check(&p, end, len);
-	string context(p, len);
+	std::string context(p, len);
 	p += len;
 
 	decode_length_and_check(&p, end, len);
-	string msg(prefix);
+	std::string msg(prefix);
 	msg.append(p, len);
 	p += len;
 
diff -ur xapian-core-1.4.21/net/serialise-error.h xapian-core-1.4.21/net/serialise-error.h
--- xapian-core-1.4.21/net/serialise-error.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/serialise-error.h	2022-11-08 16:44:01.100512621 +0100
@@ -42,7 +42,7 @@
  *
  *  Note: does not return!
  *
- *  @param error_string		The string to unserialise.
+ *  @param error_string		The std::string to unserialise.
  *  @param prefix		Optional prefix to prepend to the unserialised
  *				Error's @a msg field.
  *  @param new_context		Optional context to replace the context in
diff -ur xapian-core-1.4.21/net/serialise.h xapian-core-1.4.21/net/serialise.h
--- xapian-core-1.4.21/net/serialise.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/serialise.h	2022-11-08 16:44:01.096512634 +0100
@@ -59,8 +59,8 @@
 
 /** Unserialise a serialised Xapian::MSet object.
  *
- *  @param p	 Pointer to the start of the string to unserialise.
- *  @param p_end Pointer to the end of the string to unserialise.
+ *  @param p	 Pointer to the start of the std::string to unserialise.
+ *  @param p_end Pointer to the end of the std::string to unserialise.
  *
  *  @return	The unserialised Xapian::MSet object.
  */
diff -ur xapian-core-1.4.21/net/tcpserver.cc xapian-core-1.4.21/net/tcpserver.cc
--- xapian-core-1.4.21/net/tcpserver.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/tcpserver.cc	2022-11-08 16:44:15.596461088 +0100
@@ -126,7 +126,7 @@
 	// the same port, so we guard against that by using a named win32 mutex
 	// object (and we create it in the 'Global namespace' so that this
 	// still works in a Terminal Services environment).
-	string name = "Global\\xapian-tcpserver-listening-" + str(port);
+	std::string name = "Global\\xapian-tcpserver-listening-" + str(port);
 	if ((mutex = CreateMutex(NULL, TRUE, name.c_str())) == NULL) {
 	    // We failed to create the mutex, probably the error is
 	    // ERROR_ACCESS_DENIED, which simply means that TcpServer is
diff -ur xapian-core-1.4.21/net/tcpserver.h xapian-core-1.4.21/net/tcpserver.h
--- xapian-core-1.4.21/net/tcpserver.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/net/tcpserver.h	2022-11-08 16:44:01.100512621 +0100
@@ -57,7 +57,7 @@
 
     /** Create a listening socket ready to accept connections.
      *
-     *  @param host	hostname or address to listen on or an empty string to
+     *  @param host	hostname or address to listen on or an empty std::string to
      *			accept connections on any interface.
      *  @param port	TCP port to listen on.
      *  @param tcp_nodelay	If true, enable TCP_NODELAY option.
diff -ur xapian-core-1.4.21/queryparser/queryparser.cc xapian-core-1.4.21/queryparser/queryparser.cc
--- xapian-core-1.4.21/queryparser/queryparser.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/queryparser/queryparser.cc	2022-11-08 16:44:15.436461657 +0100
@@ -46,7 +46,7 @@
 string
 SimpleStopper::get_description() const
 {
-    string desc("Xapian::SimpleStopper(");
+    std::string desc("Xapian::SimpleStopper(");
     set<string>::const_iterator i;
     for (i = stop_words.begin(); i != stop_words.end(); ++i) {
 	if (i != stop_words.begin()) desc += ' ';
@@ -158,8 +158,8 @@
 }
 
 Query
-QueryParser::parse_query(const string &query_string, unsigned flags,
-			 const string &default_prefix)
+QueryParser::parse_query(const std::string &query_string, unsigned flags,
+			 const std::string &default_prefix)
 {
     if (!(flags & FLAG_ACCUMULATE)) {
 	internal->stoplist.clear();
@@ -180,21 +180,21 @@
 }
 
 void
-QueryParser::add_prefix(const string &field, const string &prefix)
+QueryParser::add_prefix(const std::string &field, const std::string &prefix)
 {
     Assert(internal.get());
     internal->add_prefix(field, prefix);
 }
 
 void
-QueryParser::add_prefix(const string &field, Xapian::FieldProcessor * proc)
+QueryParser::add_prefix(const std::string &field, Xapian::FieldProcessor * proc)
 {
     Assert(internal.get());
     internal->add_prefix(field, proc);
 }
 
 void
-QueryParser::add_boolean_prefix(const string &field, const string &prefix,
+QueryParser::add_boolean_prefix(const std::string &field, const std::string &prefix,
 				const string* grouping)
 {
     Assert(internal.get());
@@ -202,7 +202,7 @@
 }
 
 void
-QueryParser::add_boolean_prefix(const string &field,
+QueryParser::add_boolean_prefix(const std::string &field,
 				Xapian::FieldProcessor * proc,
 				const string* grouping)
 {
@@ -213,17 +213,17 @@
 TermIterator
 QueryParser::stoplist_begin() const
 {
-    const list<string> & sl = internal->stoplist;
+    const std::list<string> & sl = internal->stoplist;
     return TermIterator(new VectorTermList(sl.begin(), sl.end()));
 }
 
 TermIterator
-QueryParser::unstem_begin(const string &term) const
+QueryParser::unstem_begin(const std::string &term) const
 {
     struct range_adaptor : public multimap<string, string>::iterator {
 	range_adaptor(multimap<string, string>::iterator i) :
 	    multimap<string, string>::iterator(i) {}
-	const string & operator*() const { return (*this)->second; }
+	const std::string & operator*() const { return (*this)->second; }
     };
     auto range = internal->unstem.equal_range(term);
     return TermIterator(new VectorTermList(range_adaptor(range.first),
diff -ur xapian-core-1.4.21/queryparser/queryparser_internal.cc xapian-core-1.4.21/queryparser/queryparser_internal.cc
--- xapian-core-1.4.21/queryparser/queryparser_internal.cc	2022-09-22 07:29:21.000000000 +0200
+++ xapian-core-1.4.21/queryparser/queryparser_internal.cc	2022-11-08 16:44:15.440461643 +0100
@@ -134,7 +134,7 @@
 }
 
 inline bool
-prefix_needs_colon(const string & prefix, unsigned ch)
+prefix_needs_colon(const std::string & prefix, unsigned ch)
 {
     if (!U_isupper(ch) && ch != ':') return false;
     string::size_type len = prefix.length();
@@ -161,32 +161,32 @@
     State * state;
 
   public:
-    string name;
+    std::string name;
     const FieldInfo * field_info;
-    string unstemmed;
+    std::string unstemmed;
     QueryParser::stem_strategy stem;
     termpos pos;
     Query query;
 
-    Term(const string &name_, termpos pos_)
+    Term(const std::string &name_, termpos pos_)
 	: name(name_), stem(QueryParser::STEM_NONE), pos(pos_) { }
-    explicit Term(const string &name_)
+    explicit Term(const std::string &name_)
 	: name(name_), stem(QueryParser::STEM_NONE), pos(0) { }
-    Term(const string &name_, const FieldInfo * field_info_)
+    Term(const std::string &name_, const FieldInfo * field_info_)
 	: name(name_), field_info(field_info_),
 	  stem(QueryParser::STEM_NONE), pos(0) { }
     explicit Term(termpos pos_) : stem(QueryParser::STEM_NONE), pos(pos_) { }
-    Term(State * state_, const string &name_, const FieldInfo * field_info_,
-	 const string &unstemmed_,
+    Term(State * state_, const std::string &name_, const FieldInfo * field_info_,
+	 const std::string &unstemmed_,
 	 QueryParser::stem_strategy stem_ = QueryParser::STEM_NONE,
 	 termpos pos_ = 0)
 	: state(state_), name(name_), field_info(field_info_),
 	  unstemmed(unstemmed_), stem(stem_), pos(pos_) { }
     // For RANGE tokens.
-    Term(const Xapian::Query & q, const string & grouping)
+    Term(const Xapian::Query & q, const std::string & grouping)
 	: name(grouping), query(q) { }
 
-    string make_term(const string & prefix) const;
+    std::string make_term(const std::string & prefix) const;
 
     void need_positions() {
 	if (stem == QueryParser::STEM_SOME) stem = QueryParser::STEM_NONE;
@@ -194,13 +194,13 @@
 
     termpos get_termpos() const { return pos; }
 
-    string get_grouping() const {
+    std::string get_grouping() const {
 	return field_info->grouping;
     }
 
     Query * as_wildcarded_query(State * state) const;
 
-    /** Build a query for a term at the very end of the query string when
+    /** Build a query for a term at the very end of the query std::string when
      *  FLAG_PARTIAL is in use.
      *
      *  This query should match documents containing any terms which start with
@@ -210,10 +210,10 @@
      */
     Query * as_partial_query(State * state_) const;
 
-    /** Build a query for a string of CJK characters. */
+    /** Build a query for a std::string of CJK characters. */
     Query * as_cjk_query() const;
 
-    /** Handle a CJK character string in a positional context. */
+    /** Handle a CJK character std::string in a positional context. */
     void as_positional_cjk_term(Terms * terms) const;
 
     /// Range query.
@@ -246,7 +246,7 @@
 	}
     }
 
-    string stem_term(const string &term) {
+    std::string stem_term(const std::string &term) {
 	return qpi->stemmer(term);
     }
 
@@ -254,11 +254,11 @@
 	qpi->stoplist.push_back(term->name);
     }
 
-    void add_to_unstem(const string & term, const string & unstemmed) {
+    void add_to_unstem(const std::string & term, const std::string & unstemmed) {
 	qpi->unstem.insert(make_pair(term, unstemmed));
     }
 
-    Term * range(const string &a, const string &b) {
+    Term * range(const std::string &a, const std::string &b) {
 	for (auto i : qpi->rangeprocs) {
 	    Xapian::Query range_query = (i.proc)->check_range(a, b);
 	    Xapian::Query::op op = range_query.get_type();
@@ -327,9 +327,9 @@
 };
 
 string
-Term::make_term(const string & prefix) const
+Term::make_term(const std::string & prefix) const
 {
-    string term;
+    std::string term;
     if (stem != QueryParser::STEM_NONE && stem != QueryParser::STEM_ALL)
 	term += 'Z';
     if (!prefix.empty()) {
@@ -403,7 +403,7 @@
 
     for (auto&& prefix : prefixes) {
 	// First try the unstemmed term:
-	string term;
+	std::string term;
 	if (!prefix.empty()) {
 	    term += prefix;
 	    if (prefix_needs_colon(prefix, name[0])) term += ':';
@@ -499,7 +499,7 @@
     const auto& prefixes = field_info->prefixes;
     Xapian::termcount max = state_->get_max_wildcard_expansion();
     int max_type = state_->get_max_wildcard_type();
-    vector<Query> subqs;
+    std::vector<Query> subqs;
     subqs.reserve(prefixes.size());
     for (string root : prefixes) {
 	root += name;
@@ -517,11 +517,11 @@
 {
     Xapian::termcount max = state_->get_max_partial_expansion();
     int max_type = state_->get_max_partial_type();
-    vector<Query> subqs_partial; // A synonym of all the partial terms.
-    vector<Query> subqs_full; // A synonym of all the full terms.
+    std::vector<Query> subqs_partial; // A synonym of all the partial terms.
+    std::vector<Query> subqs_full; // A synonym of all the full terms.
 
     for (const string& prefix : field_info->prefixes) {
-	string root = prefix;
+	std::string root = prefix;
 	root += name;
 	// Combine with OP_OR, and apply OP_SYNONYM afterwards.
 	subqs_partial.push_back(Query(Query::OP_WILDCARD, root, max, max_type,
@@ -541,8 +541,8 @@
 Query *
 Term::as_cjk_query() const
 {
-    vector<Query> prefix_subqs;
-    vector<Query> cjk_subqs;
+    std::vector<Query> prefix_subqs;
+    std::vector<Query> cjk_subqs;
     const auto& prefixes = field_info->prefixes;
     for (const string& prefix : prefixes) {
 	for (CJKTokenIterator tk(name); tk != CJKTokenIterator(); ++tk) {
@@ -582,7 +582,7 @@
 }
 
 inline bool
-should_stem(const string & term)
+should_stem(const std::string & term)
 {
     const unsigned int SHOULD_STEM_MASK =
 	(1 << Unicode::LOWERCASE_LETTER) |
@@ -644,9 +644,9 @@
 static void yy_parse_failed(yyParser *);
 
 void
-QueryParser::Internal::add_prefix(const string &field, const string &prefix)
+QueryParser::Internal::add_prefix(const std::string &field, const std::string &prefix)
 {
-    map<string, FieldInfo>::iterator p = field_map.find(field);
+    std::map<string, FieldInfo>::iterator p = field_map.find(field);
     if (p == field_map.end()) {
 	field_map.insert(make_pair(field, FieldInfo(NON_BOOLEAN, prefix)));
     } else {
@@ -655,15 +655,15 @@
 	    throw Xapian::InvalidOperationError("Can't use add_prefix() and add_boolean_prefix() on the same field name, or add_boolean_prefix() with different values of the 'exclusive' parameter");
 	}
 	if (p->second.proc.get())
-	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and string prefixes currently not supported");
+	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and std::string prefixes currently not supported");
 	p->second.prefixes.push_back(prefix);
    }
 }
 
 void
-QueryParser::Internal::add_prefix(const string &field, FieldProcessor *proc)
+QueryParser::Internal::add_prefix(const std::string &field, FieldProcessor *proc)
 {
-    map<string, FieldInfo>::iterator p = field_map.find(field);
+    std::map<string, FieldInfo>::iterator p = field_map.find(field);
     if (p == field_map.end()) {
 	field_map.insert(make_pair(field, FieldInfo(NON_BOOLEAN, proc)));
     } else {
@@ -672,14 +672,14 @@
 	    throw Xapian::InvalidOperationError("Can't use add_prefix() and add_boolean_prefix() on the same field name, or add_boolean_prefix() with different values of the 'exclusive' parameter");
 	}
 	if (!p->second.prefixes.empty())
-	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and string prefixes currently not supported");
+	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and std::string prefixes currently not supported");
 	throw Xapian::FeatureUnavailableError("Multiple FieldProcessor objects for the same prefix currently not supported");
    }
 }
 
 void
-QueryParser::Internal::add_boolean_prefix(const string &field,
-					  const string &prefix,
+QueryParser::Internal::add_boolean_prefix(const std::string &field,
+					  const std::string &prefix,
 					  const string* grouping)
 {
     // Don't allow the empty prefix to be set as boolean as it doesn't
@@ -688,7 +688,7 @@
 	throw Xapian::UnimplementedError("Can't set the empty prefix to be a boolean filter");
     if (!grouping) grouping = &field;
     filter_type type = grouping->empty() ? BOOLEAN : BOOLEAN_EXCLUSIVE;
-    map<string, FieldInfo>::iterator p = field_map.find(field);
+    std::map<string, FieldInfo>::iterator p = field_map.find(field);
     if (p == field_map.end()) {
 	field_map.insert(make_pair(field, FieldInfo(type, prefix, *grouping)));
     } else {
@@ -697,13 +697,13 @@
 	    throw Xapian::InvalidOperationError("Can't use add_prefix() and add_boolean_prefix() on the same field name, or add_boolean_prefix() with different values of the 'exclusive' parameter"); // FIXME
 	}
 	if (p->second.proc.get())
-	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and string prefixes currently not supported");
+	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and std::string prefixes currently not supported");
 	p->second.prefixes.push_back(prefix); // FIXME grouping
    }
 }
 
 void
-QueryParser::Internal::add_boolean_prefix(const string &field,
+QueryParser::Internal::add_boolean_prefix(const std::string &field,
 					  FieldProcessor *proc,
 					  const string* grouping)
 {
@@ -713,7 +713,7 @@
 	throw Xapian::UnimplementedError("Can't set the empty prefix to be a boolean filter");
     if (!grouping) grouping = &field;
     filter_type type = grouping->empty() ? BOOLEAN : BOOLEAN_EXCLUSIVE;
-    map<string, FieldInfo>::iterator p = field_map.find(field);
+    std::map<string, FieldInfo>::iterator p = field_map.find(field);
     if (p == field_map.end()) {
 	field_map.insert(make_pair(field, FieldInfo(type, proc, *grouping)));
     } else {
@@ -722,7 +722,7 @@
 	    throw Xapian::InvalidOperationError("Can't use add_prefix() and add_boolean_prefix() on the same field name, or add_boolean_prefix() with different values of the 'exclusive' parameter"); // FIXME
 	}
 	if (!p->second.prefixes.empty())
-	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and string prefixes currently not supported");
+	    throw Xapian::FeatureUnavailableError("Mixing FieldProcessor objects and std::string prefixes currently not supported");
 	throw Xapian::FeatureUnavailableError("Multiple FieldProcessor objects for the same prefix currently not supported");
    }
 }
@@ -732,11 +732,11 @@
 				  bool cjk_ngram, bool & is_cjk_term,
 				  bool &was_acronym)
 {
-    string term;
+    std::string term;
     // Look for initials separated by '.' (e.g. P.T.O., U.N.C.L.E).
     // Don't worry if there's a trailing '.' or not.
     if (U_isupper(*it)) {
-	string t;
+	std::string t;
 	Utf8Iterator p = it;
 	do {
 	    Unicode::append_utf8(t, *p++);
@@ -789,7 +789,7 @@
 	    prevch = ch;
 	}
 	if (it != end && is_suffix(*it)) {
-	    string suff_term = term;
+	    std::string suff_term = term;
 	    Utf8Iterator p = it;
 	    // Keep trailing + (e.g. C++, Na+) or # (e.g. C#).
 	    do {
@@ -805,7 +805,7 @@
 		// the case when QueryParser::set_database() hasn't
 		// been called.
 		bool use_suff_term = false;
-		string lc = Unicode::tolower(suff_term);
+		std::string lc = Unicode::tolower(suff_term);
 		if (db.term_exists(lc)) {
 		    use_suff_term = true;
 		} else {
@@ -832,7 +832,7 @@
     // filter is a map from prefix to a query for that prefix.  Queries with
     // the same prefix are combined with OR, and the results of this are
     // combined with AND to get the full filter.
-    map<string, Query> filter;
+    std::map<string, Query> filter;
 
     ProbQuery() {}
 
@@ -888,7 +888,7 @@
 
 /// A group of terms separated only by whitespace.
 class TermGroup {
-    vector<Term *> terms;
+    std::vector<Term *> terms;
 
     /** Controls how to handle a group where all terms are stopwords.
      *
@@ -934,20 +934,20 @@
     bool default_op_is_positional = is_positional(state->default_op());
 reprocess:
     Query::op default_op = state->default_op();
-    vector<Query> subqs;
+    std::vector<Query> subqs;
     subqs.reserve(terms.size());
     if (state->flags & QueryParser::FLAG_AUTO_MULTIWORD_SYNONYMS) {
 	// Check for multi-word synonyms.
 	Database db = state->get_database();
 
-	string key;
+	std::string key;
 	vector<Term*>::size_type begin = 0;
 	vector<Term*>::size_type i = begin;
 	while (terms.size() - i > 0) {
 	    size_t longest_match = 0;
 	    // This value is never used, but GCC 4.8 warns with
 	    // -Wmaybe-uninitialized (GCC 5.4 doesn't).
-	    vector<Term*>::size_type longest_match_end = 0;
+	    std::vector<Term*>::size_type longest_match_end = 0;
 	    if (terms.size() - i >= 2) {
 		// Greedily try to match as many consecutive words as possible.
 		key = terms[i]->name;
@@ -989,7 +989,7 @@
 	    i = longest_match_end;
 	    key.resize(longest_match);
 
-	    vector<Query> subqs2;
+	    std::vector<Query> subqs2;
 	    for (auto j = begin; j != i; ++j) {
 		if (stopper && (*stopper)(terms[j]->name)) {
 		    state->add_to_stoplist(terms[j]);
@@ -1056,7 +1056,7 @@
 
 /// Some terms which form a positional sub-query.
 class Terms {
-    vector<Term *> terms;
+    std::vector<Term *> terms;
 
     /** Window size.
      *
@@ -1079,10 +1079,10 @@
     /** The list of prefixes of the terms added.
      *  This will be NULL if the terms have different prefixes.
      */
-    const vector<string>* prefixes;
+    const std::vector<string>* prefixes;
 
     Query opwindow_subq(Query::op op,
-			const vector<Query>& v,
+			const std::vector<Query>& v,
 			Xapian::termcount w) const {
 	if (op == Query::OP_AND) {
 	    return Query(op, v.begin(), v.end());
@@ -1099,7 +1099,7 @@
 	if (uniform_prefixes) {
 	    if (prefixes) {
 		for (auto&& prefix : *prefixes) {
-		    vector<Query> subqs;
+		    std::vector<Query> subqs;
 		    subqs.reserve(n_terms);
 		    for (Term* t : terms) {
 			subqs.push_back(Query(t->make_term(prefix), 1, t->pos));
@@ -1108,7 +1108,7 @@
 		}
 	    }
 	} else {
-	    vector<Query> subqs;
+	    std::vector<Query> subqs;
 	    subqs.reserve(n_terms);
 	    for (Term* t : terms) {
 		subqs.push_back(t->get_query());
@@ -1186,7 +1186,7 @@
 Term::as_positional_cjk_term(Terms * terms) const
 {
     // Add each individual CJK character to the phrase.
-    string t;
+    std::string t;
     for (Utf8Iterator it(name); it != Utf8Iterator(); ++it) {
 	Unicode::append_utf8(t, *it);
 	Term * c = new Term(state, t, field_info, unstemmed, stem, pos);
@@ -1527,7 +1527,7 @@
   int yyerrcnt;                 /* Shifts left before out of the error */
 #endif
   ParseARG_SDECL                /* A place to hold %extra_argument */
-  vector<yyStackEntry> yystack; /* The parser's stack */
+  std::vector<yyStackEntry> yystack; /* The parser's stack */
   yyParser() {
     ParseInit(this);
   }
@@ -2233,7 +2233,7 @@
       case 1: /* query ::= */
 #line 1868 "queryparser/queryparser.lemony"
 {
-    // Handle a query string with no terms in.
+    // Handle a query std::string with no terms in.
     state->query = Query();
 }
 #line 2240 "queryparser/queryparser_internal.cc"
@@ -2359,7 +2359,7 @@
       case 10: /* prob ::= RANGE */
 #line 1987 "queryparser/queryparser.lemony"
 {
-    string grouping = yymsp[0].minor.yy0->name;
+    std::string grouping = yymsp[0].minor.yy0->name;
     const Query & range = yymsp[0].minor.yy0->as_range_query();
     yymsp[0].minor.yy40 = new ProbQuery; /*P-overwrites-R*/
     yymsp[0].minor.yy40->add_filter_range(grouping, range);
@@ -2369,7 +2369,7 @@
       case 11: /* prob ::= stop_prob RANGE */
 #line 1994 "queryparser/queryparser.lemony"
 {
-    string grouping = yymsp[0].minor.yy0->name;
+    std::string grouping = yymsp[0].minor.yy0->name;
     const Query & range = yymsp[0].minor.yy0->as_range_query();
     yymsp[-1].minor.yy40->append_filter_range(grouping, range);
 }
@@ -2970,8 +2970,8 @@
 
 
 Query
-QueryParser::Internal::parse_query(const string &qs, unsigned flags,
-				   const string &default_prefix)
+QueryParser::Internal::parse_query(const std::string &qs, unsigned flags,
+				   const std::string &default_prefix)
 {
     bool cjk_ngram = (flags & FLAG_CJK_NGRAM) || CJK::is_cjk_enabled();
 
@@ -2989,7 +2989,7 @@
     corrected_query.resize(0);
 
     // Stack of prefixes, used for phrases and subexpressions.
-    list<const FieldInfo *> prefix_stack;
+    std::list<const FieldInfo *> prefix_stack;
 
     // If default_prefix is specified, use it.  Otherwise, use any list
     // that has been set for the empty prefix.
@@ -3048,7 +3048,7 @@
 	    unsigned ch = 0;
 	    while (p != end) {
 		if (ch == '.' && *p == '.') {
-		    string a;
+		    std::string a;
 		    while (it != p) {
 			Unicode::append_utf8(a, *it++);
 		    }
@@ -3058,7 +3058,7 @@
 		    // Either end of the range can be empty (for an open-ended
 		    // range) but both can't be empty.
 		    if (!a.empty() || (p != end && *p > ' ' && *p != ')')) {
-			string b;
+			std::string b;
 			// Allow any character except whitespace and ')' in the
 			// upper bound.
 			while (p != end && *p > ' ' && *p != ')') {
@@ -3231,11 +3231,11 @@
 	    // Check for a fieldname prefix (e.g. title:historical).
 	    Utf8Iterator p = find_if(it, end, is_not_wordchar);
 	    if (p != end && *p == ':' && ++p != end && *p > ' ' && *p != ')') {
-		string field;
+		std::string field;
 		p = it;
 		while (*p != ':')
 		    Unicode::append_utf8(field, *p++);
-		map<string, FieldInfo>::const_iterator f;
+		std::map<string, FieldInfo>::const_iterator f;
 		f = field_map.find(field);
 		if (f != field_map.end()) {
 		    // Special handling for prefixed fields, depending on the
@@ -3248,7 +3248,7 @@
 			if (mode == IN_GROUP || mode == IN_GROUP2)
 			    mode = DEFAULT;
 			it = p;
-			string name;
+			std::string name;
 			if (it != end && is_double_quote(*it)) {
 			    // Quoted boolean term (can contain any character).
 			    bool fancy = (*it != '"');
@@ -3333,7 +3333,7 @@
 phrased_term:
 	bool was_acronym;
 	bool is_cjk_term = false;
-	string term = parse_term(it, end, cjk_ngram, is_cjk_term, was_acronym);
+	std::string term = parse_term(it, end, cjk_ngram, is_cjk_term, was_acronym);
 
 	if ((mode == DEFAULT || mode == IN_GROUP || mode == IN_GROUP2) &&
 	    (flags & FLAG_BOOLEAN) &&
@@ -3342,7 +3342,7 @@
 	    !field_info &&
 	    term.size() >= 2 && term.size() <= 4 && U_isalpha(term[0])) {
 	    // Boolean operators.
-	    string op = term;
+	    std::string op = term;
 	    if (flags & FLAG_BOOLEAN_ANY_CASE) {
 		for (string::iterator i = op.begin(); i != op.end(); ++i) {
 		    *i = C_toupper(*i);
@@ -3410,7 +3410,7 @@
 	Assert(field_info->type == NON_BOOLEAN);
 
 	{
-	    string unstemmed_term(term);
+	    std::string unstemmed_term(term);
 	    term = Unicode::tolower(term);
 
 	    // Reuse stem_strategy - STEM_SOME here means "stem terms except
@@ -3482,7 +3482,7 @@
 		for (const string& prefix : prefixes) {
 		    if (!prefix.empty())
 			continue;
-		    const string & suggest = db.get_spelling_suggestion(term);
+		    const std::string & suggest = db.get_spelling_suggestion(term);
 		    if (!suggest.empty()) {
 			if (corrected_query.empty()) corrected_query = qs;
 			size_t term_end_index = it.raw() - qs.data();
diff -ur xapian-core-1.4.21/queryparser/queryparser_internal.h xapian-core-1.4.21/queryparser/queryparser_internal.h
--- xapian-core-1.4.21/queryparser/queryparser_internal.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/queryparser/queryparser_internal.h	2022-11-08 16:48:12.763618017 +0100
@@ -32,7 +32,7 @@
 #include <list>
 #include <map>
 
-using namespace std;
+using std::string;
 
 class State;
 
@@ -43,10 +43,10 @@
     /// The type of this field.
     filter_type type;
 
-    string grouping;
+    std::string grouping;
 
     /// Field prefix strings.
-    vector<string> prefixes;
+    std::vector<string> prefixes;
 
     /// Field processor.  Currently only one is supported.
     Xapian::Internal::opt_intrusive_ptr<Xapian::FieldProcessor> proc;
@@ -89,16 +89,16 @@
     Query::op default_op;
     const char * errmsg;
     Database db;
-    list<string> stoplist;
-    multimap<string, string> unstem;
+    std::list<string> stoplist;
+    std::multimap<string, string> unstem;
 
     // Map "from" -> "A" ; "subject" -> "C" ; "newsgroups" -> "G" ;
     // "foobar" -> "XFOO". FIXME: it does more than this now!
-    map<string, FieldInfo> field_map;
+    std::map<string, FieldInfo> field_map;
 
-    list<RangeProc> rangeprocs;
+    std::list<RangeProc> rangeprocs;
 
-    string corrected_query;
+    std::string corrected_query;
 
     Xapian::termcount max_wildcard_expansion;
 
@@ -108,14 +108,14 @@
 
     int max_partial_type;
 
-    void add_prefix(const string &field, const string &prefix);
+    void add_prefix(const std::string &field, const std::string &prefix);
 
-    void add_prefix(const string &field, Xapian::FieldProcessor *proc);
+    void add_prefix(const std::string &field, Xapian::FieldProcessor *proc);
 
-    void add_boolean_prefix(const string &field, const string &prefix,
+    void add_boolean_prefix(const std::string &field, const std::string &prefix,
 			    const string* grouping);
 
-    void add_boolean_prefix(const string &field, Xapian::FieldProcessor *proc,
+    void add_boolean_prefix(const std::string &field, Xapian::FieldProcessor *proc,
 			    const string* grouping);
 
     std::string parse_term(Utf8Iterator &it, const Utf8Iterator &end,
@@ -129,7 +129,7 @@
 	max_wildcard_type(Xapian::Query::WILDCARD_LIMIT_ERROR),
 	max_partial_type(Xapian::Query::WILDCARD_LIMIT_MOST_FREQUENT) { }
 
-    Query parse_query(const string & query_string, unsigned int flags, const string & default_prefix);
+    Query parse_query(const std::string & query_string, unsigned int flags, const std::string & default_prefix);
 };
 
 }
diff -ur xapian-core-1.4.21/queryparser/termgenerator.cc xapian-core-1.4.21/queryparser/termgenerator.cc
--- xapian-core-1.4.21/queryparser/termgenerator.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/queryparser/termgenerator.cc	2022-11-08 16:44:15.436461657 +0100
@@ -108,7 +108,7 @@
 void
 TermGenerator::index_text(const Xapian::Utf8Iterator & itor,
 			  Xapian::termcount weight,
-			  const string & prefix)
+			  const std::string & prefix)
 {
     internal->index_text(itor, weight, prefix, true);
 }
@@ -116,7 +116,7 @@
 void
 TermGenerator::index_text_without_positions(const Xapian::Utf8Iterator & itor,
 					    Xapian::termcount weight,
-					    const string & prefix)
+					    const std::string & prefix)
 {
     internal->index_text(itor, weight, prefix, false);
 }
@@ -142,7 +142,7 @@
 string
 TermGenerator::get_description() const
 {
-    string s("Xapian::TermGenerator(stem=");
+    std::string s("Xapian::TermGenerator(stem=");
     s += internal->stemmer.get_description();
     if (internal->stopper.get()) {
 	s += ", stopper set";
diff -ur xapian-core-1.4.21/queryparser/termgenerator_internal.cc xapian-core-1.4.21/queryparser/termgenerator_internal.cc
--- xapian-core-1.4.21/queryparser/termgenerator_internal.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/queryparser/termgenerator_internal.cc	2022-11-08 16:44:15.432461672 +0100
@@ -151,7 +151,7 @@
 	    ++itor;
 	}
 
-	string term;
+	std::string term;
 	// Look for initials separated by '.' (e.g. P.T.O., U.N.C.L.E).
 	// Don't worry if there's a trailing '.' or not.
 	if (U_isupper(*itor)) {
@@ -248,7 +248,7 @@
 
 void
 TermGenerator::Internal::index_text(Utf8Iterator itor, termcount wdf_inc,
-				    const string & prefix, bool with_positions)
+				    const std::string & prefix, bool with_positions)
 {
     bool cjk_ngram = (flags & FLAG_CJK_NGRAM) || CJK::is_cjk_enabled();
 
@@ -266,7 +266,7 @@
 // don't allow `this` here.
 	, this
 #endif
-	](const string & term, bool positional, const Utf8Iterator &) {
+	](const std::string & term, bool positional, const Utf8Iterator &) {
 	    if (term.size() > max_word_length) return true;
 
 	    if (current_stop_mode == TermGenerator::STOP_ALL &&
@@ -306,7 +306,7 @@
 	    // Add stemmed form without positional information.
 	    const string& stem = stemmer(term);
 	    if (rare(stem.empty())) return true;
-	    string stemmed_term;
+	    std::string stemmed_term;
 	    if (strategy != TermGenerator::STEM_ALL) {
 		stemmed_term += "Z";
 	    }
@@ -363,11 +363,11 @@
 
     void done();
 
-    bool drain(const string & input,
-	       const string & hi_start,
-	       const string & hi_end,
-	       const string & omit,
-	       string & output);
+    bool drain(const std::string & input,
+	       const std::string & hi_start,
+	       const std::string & hi_end,
+	       const std::string & omit,
+	       std::string & output);
 };
 
 #define DECAY 2.0
@@ -540,11 +540,11 @@
 }
 
 inline bool
-SnipPipe::drain(const string & input,
-		const string & hi_start,
-		const string & hi_end,
-		const string & omit,
-		string & output)
+SnipPipe::drain(const std::string & input,
+		const std::string & hi_start,
+		const std::string & hi_end,
+		const std::string & omit,
+		std::string & output)
 {
     if (best_pipe.empty() && !pipe.empty()) {
 	swap(best_pipe, pipe);
@@ -681,9 +681,9 @@
 
 static void
 check_query(const Xapian::Query & query,
-	    list<vector<string>> & exact_phrases,
+	    std::list<vector<string>> & exact_phrases,
 	    unordered_map<string, double> & loose_terms,
-	    list<string> & wildcards,
+	    std::list<string> & wildcards,
 	    size_t & longest_phrase)
 {
     // FIXME: OP_NEAR, non-tight OP_PHRASE, OP_PHRASE with non-term subqueries
@@ -709,7 +709,7 @@
 
 	    // Tight phrase of terms.
 	    exact_phrases.push_back(vector<string>());
-	    vector<string> & terms = exact_phrases.back();
+	    std::vector<string> & terms = exact_phrases.back();
 	    terms.reserve(n_subqs);
 	    for (size_t i = 0; i != n_subqs; ++i) {
 		Xapian::Query q = query.get_subquery(i);
@@ -730,7 +730,7 @@
 static double*
 check_term(unordered_map<string, double> & loose_terms,
 	   const Xapian::Weight::Internal * stats,
-	   const string & term,
+	   const std::string & term,
 	   double max_tw)
 {
     auto it = loose_terms.find(term);
@@ -750,13 +750,13 @@
 }
 
 string
-MSet::Internal::snippet(const string & text,
+MSet::Internal::snippet(const std::string & text,
 			size_t length,
 			const Xapian::Stem & stemmer,
 			unsigned flags,
-			const string & hi_start,
-			const string & hi_end,
-			const string & omit) const
+			const std::string & hi_start,
+			const std::string & hi_end,
+			const std::string & omit) const
 {
     if (hi_start.empty() && hi_end.empty() && text.size() <= length) {
 	// Too easy!
@@ -787,21 +787,21 @@
     }
     SnipPipe snip(length);
 
-    list<vector<string>> exact_phrases;
+    std::list<vector<string>> exact_phrases;
     unordered_map<string, double> loose_terms;
-    list<string> wildcards;
+    std::list<string> wildcards;
     size_t longest_phrase = 0;
     check_query(query, exact_phrases, loose_terms,
 		wildcards, longest_phrase);
 
-    vector<double> exact_phrases_relevance;
+    std::vector<double> exact_phrases_relevance;
     exact_phrases_relevance.reserve(exact_phrases.size());
     for (auto&& terms : exact_phrases) {
 	// FIXME: What relevance to use?
 	exact_phrases_relevance.push_back(max_tw * terms.size());
     }
 
-    vector<double> wildcards_relevance;
+    std::vector<double> wildcards_relevance;
     wildcards_relevance.reserve(exact_phrases.size());
     for (auto&& pattern : wildcards) {
 	// FIXME: What relevance to use?
@@ -813,12 +813,12 @@
     // between calls to MSet::snippet() on the same object.
     unordered_map<string, double>& background = snippet_bg_relevance;
 
-    vector<string> phrase;
+    std::vector<string> phrase;
     if (longest_phrase) phrase.resize(longest_phrase - 1);
     size_t phrase_next = 0;
     bool matchfound = false;
     parse_terms(Utf8Iterator(text), cjk_ngram, true,
-	[&](const string & term, bool positional, const Utf8Iterator & it) {
+	[&](const std::string & term, bool positional, const Utf8Iterator & it) {
 	    // FIXME: Don't hardcode this here.
 	    const size_t max_word_length = 64;
 
@@ -861,7 +861,7 @@
 		    goto relevance_done;
 		}
 
-		string stem = "Z";
+		std::string stem = "Z";
 		stem += stemmer(term);
 		relevance = check_term(loose_terms, stats, stem, max_tw);
 		if (relevance) {
@@ -923,7 +923,7 @@
 		if (queryterms.find(term) != queryterms.end()) {
 		    relevance = term.size() * 3;
 		} else {
-		    string stem = "Z";
+		    std::string stem = "Z";
 		    stem += stemmer(term);
 		    if (queryterms.find(stem) != queryterms.end()) {
 			relevance = term.size() * 2;
@@ -970,7 +970,7 @@
     snip.done();
 
     // Put together the snippet.
-    string result;
+    std::string result;
     if (matchfound || (flags & SNIPPET_EMPTY_WITHOUT_MATCH) == 0) {
 	while (snip.drain(text, hi_start, hi_end, omit, result)) { }
     }
diff -ur xapian-core-1.4.21/tests/api_anydb.cc xapian-core-1.4.21/tests/api_anydb.cc
--- xapian-core-1.4.21/tests/api_anydb.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_anydb.cc	2022-11-08 16:44:15.544461274 +0100
@@ -61,13 +61,13 @@
 
 static Xapian::Query
 query(Xapian::Query::op op,
-      const string & t1 = string(), const string & t2 = string(),
-      const string & t3 = string(), const string & t4 = string(),
-      const string & t5 = string(), const string & t6 = string(),
-      const string & t7 = string(), const string & t8 = string(),
-      const string & t9 = string(), const string & t10 = string())
+      const std::string & t1 = string(), const std::string & t2 = string(),
+      const std::string & t3 = string(), const std::string & t4 = string(),
+      const std::string & t5 = string(), const std::string & t6 = string(),
+      const std::string & t7 = string(), const std::string & t8 = string(),
+      const std::string & t9 = string(), const std::string & t10 = string())
 {
-    vector<string> v;
+    std::vector<string> v;
     Xapian::Stem stemmer("english");
     if (!t1.empty()) v.push_back(stemmer(t1));
     if (!t2.empty()) v.push_back(stemmer(t2));
@@ -84,13 +84,13 @@
 
 static Xapian::Query
 query(Xapian::Query::op op, Xapian::termcount parameter,
-      const string & t1 = string(), const string & t2 = string(),
-      const string & t3 = string(), const string & t4 = string(),
-      const string & t5 = string(), const string & t6 = string(),
-      const string & t7 = string(), const string & t8 = string(),
-      const string & t9 = string(), const string & t10 = string())
+      const std::string & t1 = string(), const std::string & t2 = string(),
+      const std::string & t3 = string(), const std::string & t4 = string(),
+      const std::string & t5 = string(), const std::string & t6 = string(),
+      const std::string & t7 = string(), const std::string & t8 = string(),
+      const std::string & t9 = string(), const std::string & t10 = string())
 {
-    vector<string> v;
+    std::vector<string> v;
     Xapian::Stem stemmer("english");
     if (!t1.empty()) v.push_back(stemmer(t1));
     if (!t2.empty()) v.push_back(stemmer(t2));
@@ -106,7 +106,7 @@
 }
 
 static Xapian::Query
-query(const string &t)
+query(const std::string &t)
 {
     return Xapian::Query(Xapian::Stem("english")(t));
 }
@@ -151,7 +151,7 @@
     TEST_EQUAL(mymset.get_uncollapsed_matches_upper_bound(), 0);
     TEST_EQUAL(mymset.get_uncollapsed_matches_estimated(), 0);
 
-    vector<Xapian::Query> v;
+    std::vector<Xapian::Query> v;
     enquire.set_query(Xapian::Query(Xapian::Query::OP_AND, v.begin(), v.end()));
     mymset = enquire.get_mset(0, 10);
     TEST_MSET_SIZE(mymset, 0);
@@ -566,7 +566,7 @@
 
 class EvenParityExpandFunctor : public Xapian::ExpandDecider {
   public:
-    bool operator()(const string & tname) const {
+    bool operator()(const std::string & tname) const {
 	unsigned long sum = 0;
 	for (unsigned ch : tname) {
 	    sum += ch;
@@ -656,7 +656,7 @@
     // Choose the first char in the first term as prefix.
     Xapian::ESetIterator j = myeset_orig.begin();
     TEST(myeset_orig.size() >= 1);
-    string prefix(*j, 0, 1);
+    std::string prefix(*j, 0, 1);
     Xapian::ExpandDeciderFilterPrefix myfunctor(prefix);
 
     for ( ; j != myeset_orig.end(); ++j) {
@@ -851,7 +851,7 @@
 // tests the allow query terms expand option
 DEFINE_TESTCASE(allowqterms1, backend) {
     Xapian::Enquire enquire(get_database("apitest_simpledata"));
-    string term = "paragraph";
+    std::string term = "paragraph";
     enquire.set_query(Xapian::Query(term));
 
     Xapian::MSet mymset = enquire.get_mset(0, 10);
@@ -983,7 +983,7 @@
 
 // tests that get_matching_terms() returns the terms in the right order
 DEFINE_TESTCASE(getmterms1, backend) {
-    list<string> answers_list;
+    std::list<string> answers_list;
     answers_list.push_back("one");
     answers_list.push_back("two");
     answers_list.push_back("three");
@@ -1005,14 +1005,14 @@
     Xapian::MSet mymset = enquire.get_mset(0, 10);
 
     TEST_MSET_SIZE(mymset, 1);
-    list<string> list(enquire.get_matching_terms_begin(mymset.begin()),
+    std::list<string> list(enquire.get_matching_terms_begin(mymset.begin()),
 			  enquire.get_matching_terms_end(mymset.begin()));
     TEST(list == answers_list);
 }
 
 // tests that get_matching_terms() returns the terms only once
 DEFINE_TESTCASE(getmterms2, backend) {
-    list<string> answers_list;
+    std::list<string> answers_list;
     answers_list.push_back("one");
     answers_list.push_back("two");
     answers_list.push_back("three");
@@ -1033,7 +1033,7 @@
     Xapian::MSet mymset = enquire.get_mset(0, 10);
 
     TEST_MSET_SIZE(mymset, 1);
-    list<string> list(enquire.get_matching_terms_begin(mymset.begin()),
+    std::list<string> list(enquire.get_matching_terms_begin(mymset.begin()),
 			  enquire.get_matching_terms_end(mymset.begin()));
     TEST(list == answers_list);
 }
@@ -1093,7 +1093,7 @@
 // as absentterm1, but setting query from a vector of terms
 DEFINE_TESTCASE(absentterm2, backend) {
     Xapian::Enquire enquire(get_database("apitest_simpledata"));
-    vector<string> terms;
+    std::vector<string> terms;
     terms.push_back("frink");
 
     Xapian::Query query(Xapian::Query::OP_OR, terms.begin(), terms.end());
@@ -1239,7 +1239,7 @@
 
     Xapian::Query myquery1 = query(Xapian::Query::OP_AND, "word", "search");
 
-    vector<Xapian::Query> qs;
+    std::vector<Xapian::Query> qs;
     qs.push_back(query("this"));
     qs.push_back(query(Xapian::Query::OP_AND, "word", "search"));
     Xapian::Query myquery2(Xapian::Query::OP_ELITE_SET,
@@ -1261,7 +1261,7 @@
 
     Xapian::Query myquery1 = query(Xapian::Query::OP_AND, "word", "search");
 
-    vector<Xapian::Query> qs;
+    std::vector<Xapian::Query> qs;
     qs.push_back(query("this"));
     qs.push_back(query(Xapian::Query::OP_AND, "word", "search"));
     Xapian::Query myquery2(Xapian::Query::OP_ELITE_SET,
@@ -1301,11 +1301,11 @@
     // make a query
     Xapian::Stem stemmer("english");
 
-    string term1 = stemmer("word");
-    string term2 = stemmer("rubbish");
-    string term3 = stemmer("banana");
+    std::string term1 = stemmer("word");
+    std::string term2 = stemmer("rubbish");
+    std::string term3 = stemmer("banana");
 
-    vector<string> terms;
+    std::vector<string> terms;
     terms.push_back(term1);
     terms.push_back(term2);
     terms.push_back(term3);
@@ -1392,7 +1392,7 @@
     Xapian::Database mydb1(get_database("apitest_simpledata"));
     Xapian::Enquire enquire1(mydb1);
 
-    vector<string> v;
+    std::vector<string> v;
     for (int i = 0; i != 3; ++i) {
 	v.push_back("simpl");
 	v.push_back("queri");
@@ -1433,7 +1433,7 @@
     Xapian::ESet eset2 = enquire.get_eset(1000, rset2);
 
     // search for weight of term 'another'
-    string theterm = stemmer("another");
+    std::string theterm = stemmer("another");
 
     double wt1 = 0;
     double wt2 = 0;
@@ -1473,9 +1473,9 @@
     // make a query
     Xapian::Stem stemmer("english");
 
-    string term1 = stemmer("word");
-    string term2 = stemmer("inmemory");
-    string term3 = stemmer("flibble");
+    std::string term1 = stemmer("word");
+    std::string term2 = stemmer("inmemory");
+    std::string term3 = stemmer("flibble");
 
     Xapian::Query myquery(Xapian::Query::OP_OR,
 		    Xapian::Query(term1),
@@ -1522,8 +1522,8 @@
     // make a query
     Xapian::Stem stemmer("english");
 
-    string term1 = stemmer("paragraph");
-    string term2 = stemmer("another");
+    std::string term1 = stemmer("paragraph");
+    std::string term2 = stemmer("another");
 
     enquire.set_query(Xapian::Query(term1));
     Xapian::MSet mset0 = enquire.get_mset(0, 10);
@@ -1733,11 +1733,11 @@
     Xapian::TermIterator t_clone(t);
     TEST_EQUAL(t, t_clone);
 
-    vector<string> v(t, tend);
+    std::vector<string> v(t, tend);
 
     t = db.termlist_begin(1);
     tend = db.termlist_end(1);
-    vector<string>::const_iterator i;
+    std::vector<string>::const_iterator i;
     for (i = v.begin(); i != v.end(); ++i) {
 	TEST_NOT_EQUAL(t, tend);
 	TEST_EQUAL(*i, *t);
@@ -1821,7 +1821,7 @@
     TEST_EQUAL(count, 1);
 
     for (Xapian::valueno value_no = 0; value_no < 7; ++value_no) {
-	string value = mymset.begin().get_document().get_value(value_no);
+	std::string value = mymset.begin().get_document().get_value(value_no);
 	TEST_NOT_EQUAL(value, "");
 	if (value_no == 0) {
 	    TEST(value.size() > 262);
@@ -1842,7 +1842,7 @@
     Xapian::Enquire enquire(get_database("apitest_simpledata"));
     Xapian::Stem stemmer("english");
 
-    vector<string> terms;
+    std::vector<string> terms;
     terms.push_back(stemmer("this"));
     terms.push_back(stemmer("word"));
     terms.push_back(stemmer("of"));
@@ -1867,7 +1867,7 @@
     Xapian::Enquire enquire(get_database("apitest_simpledata"));
     Xapian::Stem stemmer("english");
 
-    vector<string> terms;
+    std::vector<string> terms;
     terms.push_back(stemmer("this"));
     terms.push_back(stemmer("word"));
     terms.push_back(stemmer("of"));
@@ -1906,7 +1906,7 @@
 // test whether operators with no elements work as a null query
 DEFINE_TESTCASE(emptyop1, backend) {
     Xapian::Enquire enquire(get_database("apitest_simpledata"));
-    vector<Xapian::Query> nullvec;
+    std::vector<Xapian::Query> nullvec;
 
     Xapian::Query query1(Xapian::Query::OP_XOR, nullvec.begin(), nullvec.end());
 
@@ -2251,9 +2251,9 @@
     // First, build a vector of docids matching the first part of the query,
     // and append the non-duplicate docids matching the second part of the
     // query.
-    vector<Xapian::docid> ids1;
+    std::vector<Xapian::docid> ids1;
     set<Xapian::docid> idsin1;
-    vector<Xapian::docid> ids3;
+    std::vector<Xapian::docid> ids3;
 
     enq.set_query(query1);
     Xapian::MSet mset1 = enq.get_mset(0, 20);
@@ -2274,7 +2274,7 @@
     ids1.insert(ids1.end(), ids3.begin(), ids3.end());
 
     // Now, run the combined query and build a vector of the matching docids.
-    vector<Xapian::docid> ids5;
+    std::vector<Xapian::docid> ids5;
     enq.set_query(query5);
     Xapian::MSet mset5 = enq.get_mset(0, 20);
     for (i = mset5.begin(); i != mset5.end(); ++i) {
@@ -2342,7 +2342,7 @@
 DEFINE_TESTCASE(uuid1, backend && !multi) {
     SKIP_TEST_FOR_BACKEND("inmemory");
     Xapian::Database db = get_database("apitest_simpledata");
-    string uuid1 = db.get_uuid();
+    std::string uuid1 = db.get_uuid();
     TEST_EQUAL(uuid1.size(), 36);
 
     // A database with no sub-databases has an empty UUID.
diff -ur xapian-core-1.4.21/tests/api_backend.cc xapian-core-1.4.21/tests/api_backend.cc
--- xapian-core-1.4.21/tests/api_backend.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_backend.cc	2022-11-08 16:44:15.528461330 +0100
@@ -60,7 +60,7 @@
     try {
 	Xapian::WritableDatabase db = get_named_writable_database("lockfileumask1");
 
-	string path = get_named_writable_database_path("lockfileumask1");
+	std::string path = get_named_writable_database_path("lockfileumask1");
 	path += "/flintlock";
 
 	struct stat statbuf;
@@ -308,7 +308,7 @@
 DEFINE_TESTCASE(lockfilealreadyopen1, chert || glass) {
     // Ensure database has been created.
     (void)get_named_writable_database("lockfilealreadyopen1");
-    string path = get_named_writable_database_path("lockfilealreadyopen1");
+    std::string path = get_named_writable_database_path("lockfilealreadyopen1");
     int fd = ::open((path + "/flintlock").c_str(), O_RDONLY);
     TEST(fd != -1);
     try {
@@ -576,7 +576,7 @@
 }
 
 static void
-make_msize1_db(Xapian::WritableDatabase &db, const string &)
+make_msize1_db(Xapian::WritableDatabase &db, const std::string &)
 {
     const char * value0 =
 	"ABBCDEFGHIJKLMMNOPQQRSTTUUVVWXYZZaabcdefghhijjkllmnopqrsttuvwxyz";
@@ -626,7 +626,7 @@
 }
 
 static void
-make_msize2_db(Xapian::WritableDatabase &db, const string &)
+make_msize2_db(Xapian::WritableDatabase &db, const std::string &)
 {
     const char * value0 = "AAABCDEEFGHIIJJKLLMNNOOPPQQRSTTUVWXYZ";
     const char * value1 = "MLEMNMLMLMEDEDEMLEMLMLMLPOAHGF";
@@ -674,7 +674,7 @@
 }
 
 static void
-make_xordecay1_db(Xapian::WritableDatabase &db, const string &)
+make_xordecay1_db(Xapian::WritableDatabase &db, const std::string &)
 {
     for (int n = 1; n != 50; ++n) {
 	Xapian::Document doc;
@@ -702,7 +702,7 @@
 }
 
 static void
-make_ordecay_db(Xapian::WritableDatabase &db, const string &)
+make_ordecay_db(Xapian::WritableDatabase &db, const std::string &)
 {
     const char * p = "VJ=QC]LUNTaARLI;715RR^];A4O=P4ZG<2CS4EM^^VS[A6QENR";
     for (int d = 0; p[d]; ++d) {
@@ -757,7 +757,7 @@
 }
 
 static void
-make_orcheck_db(Xapian::WritableDatabase &db, const string &)
+make_orcheck_db(Xapian::WritableDatabase &db, const std::string &)
 {
     static const unsigned t1[] = {2, 4, 6, 8, 10};
     static const unsigned t2[] = {6, 7, 8, 11, 12, 13, 14, 15, 16, 17};
@@ -1095,7 +1095,7 @@
 // but the uncorrected size was passed to the base file.  Also, abort() was
 // called on 0.
 DEFINE_TESTCASE(blocksize1, chert || glass) {
-    string db_dir = "." + get_dbtype();
+    std::string db_dir = "." + get_dbtype();
     mkdir(db_dir.c_str(), 0755);
     db_dir += "/db__blocksize1";
     int flags;
@@ -1121,7 +1121,7 @@
 
 /// Feature test for Xapian::DB_NO_TERMLIST.
 DEFINE_TESTCASE(notermlist1, glass) {
-    string db_dir = "." + get_dbtype();
+    std::string db_dir = "." + get_dbtype();
     mkdir(db_dir.c_str(), 0755);
     db_dir += "/db__notermlist1";
     int flags = Xapian::DB_CREATE|Xapian::DB_NO_TERMLIST;
@@ -1168,7 +1168,7 @@
  */
 DEFINE_TESTCASE(readonlyparentdir1, chert || glass) {
 #if !defined __WIN32__ && !defined __CYGWIN__ && !defined __OS2__
-    string path = get_named_writable_database_path("readonlyparentdir1");
+    std::string path = get_named_writable_database_path("readonlyparentdir1");
     // Fix permissions if the previous test was killed.
     (void)chmod(path.c_str(), 0700);
     mkdir(path.c_str(), 0777);
@@ -1192,7 +1192,7 @@
 }
 
 static void
-make_phrasebug1_db(Xapian::WritableDatabase &db, const string &)
+make_phrasebug1_db(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_posting("hurricane", 199881);
@@ -1247,7 +1247,7 @@
 	} catch (const Xapian::DatabaseLockError &) {
 	    if (write(fds[0], "l", 1)) { }
 	} catch (const Xapian::Error &e) {
-	    const string & m = e.get_description();
+	    const std::string & m = e.get_description();
 	    if (write(fds[0], m.data(), m.size())) { }
 	} catch (...) {
 	    if (write(fds[0], "o", 1)) { }
@@ -1423,8 +1423,8 @@
 
 	for (int i = free_id; i <= free_id + ITEMS; ++i) {
 	    Xapian::Document doc;
-	    const string & id = str(i);
-	    string qterm = "Q" + id;
+	    const std::string & id = str(i);
+	    std::string qterm = "Q" + id;
 	    doc.add_value(0, id);
 	    doc.add_boolean_term(qterm);
 	    wdb.replace_document(qterm, doc);
@@ -1450,9 +1450,9 @@
 
     // Check all results are in key order - the bug was that they were sorted
     // by docid instead with multiple remote databases.
-    string old_key;
+    std::string old_key;
     for (Xapian::MSetIterator i = mset.begin(); i != mset.end(); ++i) {
-	string key = db.get_document(*i).get_value(0);
+	std::string key = db.get_document(*i).get_value(0);
 	TEST(old_key <= key);
 	swap(old_key, key);
     }
@@ -1471,8 +1471,8 @@
     off_t offset = 1234;
 
     Xapian::Database db = get_database("apitest_simpledata");
-    const string & db_path = get_database_path("apitest_simpledata");
-    const string & tmp_path = db_path + "-embedded";
+    const std::string & db_path = get_database_path("apitest_simpledata");
+    const std::string & tmp_path = db_path + "-embedded";
     ofstream out(tmp_path, fstream::trunc|fstream::binary);
     out.seekp(offset);
     out << ifstream(db_path, fstream::binary).rdbuf();
@@ -1731,7 +1731,7 @@
 DEFINE_TESTCASE(allterms7, backend) {
     Xapian::Database db = get_database("etext");
     for (auto i = db.allterms_begin(); i != db.allterms_end(); ++i) {
-	string term = *i;
+	std::string term = *i;
 	TEST(db.get_termfreq(term) > 0);
 	TEST(db.postlist_begin(term) != db.postlist_end(term));
     }
@@ -1747,7 +1747,7 @@
     Xapian::Enquire enquire{db};
     // Test up to a length longer than any backend supports.
     const unsigned MAX_LEN = 300;
-    string term;
+    std::string term;
     term.reserve(MAX_LEN);
     while (term.size() < MAX_LEN) {
 	term += 'x';
diff -ur xapian-core-1.4.21/tests/api_closedb.cc xapian-core-1.4.21/tests/api_closedb.cc
--- xapian-core-1.4.21/tests/api_closedb.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_closedb.cc	2022-11-08 16:44:15.552461245 +0100
@@ -221,7 +221,7 @@
     // Dup stdout to the fds which the database was using, to try to catch
     // issues with lingering references to closed fds (regression test for
     // early development versions of honey).
-    vector<int> fds;
+    std::vector<int> fds;
     for (int i = 0; i != 6; ++i) {
 	fds.push_back(dup(1));
     }
@@ -262,7 +262,7 @@
 /// Check API methods which might either work or throw an exception.
 DEFINE_TESTCASE(closedb3, backend) {
     Xapian::Database db(get_database("etext"));
-    const string & uuid = db.get_uuid();
+    const std::string & uuid = db.get_uuid();
     db.close();
     try {
 	TEST_EQUAL(db.get_uuid(), uuid);
diff -ur xapian-core-1.4.21/tests/api_collapse.cc xapian-core-1.4.21/tests/api_collapse.cc
--- xapian-core-1.4.21/tests/api_collapse.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_collapse.cc	2022-11-08 16:44:15.504461416 +0100
@@ -39,7 +39,7 @@
     Xapian::MSet full_mset = enquire.get_mset(0, db.get_doccount());
 
     for (Xapian::valueno slot = 0; slot < 10; ++slot) {
-	map<string, Xapian::doccount> tally;
+	std::map<string, Xapian::doccount> tally;
 	for (Xapian::docid did = 1; did <= db.get_doccount(); ++did) {
 	    ++tally[db.get_document(did).get_value(slot)];
 	}
@@ -51,7 +51,7 @@
 
 	    // Check the collapse MSet size is as expected.
 	    Xapian::doccount expect_size = 0;
-	    map<string, Xapian::doccount>::const_iterator i;
+	    std::map<string, Xapian::doccount>::const_iterator i;
 	    for (i = tally.begin(); i != tally.end(); ++i) {
 		if (i->first.empty() || i->second <= cmax) {
 		    expect_size += i->second;
@@ -63,9 +63,9 @@
 
 	    // Check that the right number of documents with each collapse key
 	    // value are left after collapsing.
-	    map<string, Xapian::doccount> seen;
+	    std::map<string, Xapian::doccount> seen;
 	    for (Xapian::MSetIterator j = mset.begin(); j != mset.end(); ++j) {
-		const string & key = j.get_collapse_key();
+		const std::string & key = j.get_collapse_key();
 		TEST(tally.find(key) != tally.end());
 		++seen[key];
 	    }
diff -ur xapian-core-1.4.21/tests/api_compact.cc xapian-core-1.4.21/tests/api_compact.cc
--- xapian-core-1.4.21/tests/api_compact.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_compact.cc	2022-11-08 16:44:15.532461315 +0100
@@ -48,7 +48,7 @@
 using namespace std;
 
 static void
-make_sparse_db(Xapian::WritableDatabase &db, const string & s)
+make_sparse_db(Xapian::WritableDatabase &db, const std::string & s)
 {
     // Need non-const pointer for strtoul(), but data isn't modified.
     char * p = const_cast<char *>(s.c_str());
@@ -74,7 +74,7 @@
 		db.delete_document(first);
 	    } else {
 		Xapian::Document doc;
-		string id = str(first);
+		std::string id = str(first);
 		doc.set_data(id);
 		doc.add_term("Q" + str(first));
 		doc.add_term(string(first % 7 + 1, char((first % 26) + 'a')));
@@ -90,7 +90,7 @@
 }
 
 static void
-check_sparse_uid_terms(const string & path)
+check_sparse_uid_terms(const std::string & path)
 {
     Xapian::Database db(path);
     Xapian::TermIterator t;
@@ -103,21 +103,21 @@
 
 // With multi the docids in the shards change the behaviour.
 DEFINE_TESTCASE(compactnorenumber1, compact && generated && !multi) {
-    string a = get_database_path("compactnorenumber1a", make_sparse_db,
+    std::string a = get_database_path("compactnorenumber1a", make_sparse_db,
 				 "5-7 24 76 987 1023-1027 9999 !9999");
-    string a_uuid;
+    std::string a_uuid;
     {
 	Xapian::Database db(a);
 	a_uuid = db.get_uuid();
     }
-    string b = get_database_path("compactnorenumber1b", make_sparse_db,
+    std::string b = get_database_path("compactnorenumber1b", make_sparse_db,
 				 "1027-1030");
-    string c = get_database_path("compactnorenumber1c", make_sparse_db,
+    std::string c = get_database_path("compactnorenumber1c", make_sparse_db,
 				 "1028-1040");
-    string d = get_database_path("compactnorenumber1d", make_sparse_db,
+    std::string d = get_database_path("compactnorenumber1d", make_sparse_db,
 				 "3000 999999 !999999");
 
-    string out = get_compaction_output_path("compactnorenumber1out");
+    std::string out = get_compaction_output_path("compactnorenumber1out");
 
     rm_rf(out);
     {
@@ -132,7 +132,7 @@
 	Xapian::Database db(out);
 	// xapian-compact should change the UUID of the database, but didn't
 	// prior to 1.0.18/1.1.4.
-	string out_uuid = db.get_uuid();
+	std::string out_uuid = db.get_uuid();
 	TEST_NOT_EQUAL(a_uuid, out_uuid);
 	TEST_EQUAL(out_uuid.size(), 36);
 	TEST_NOT_EQUAL(out_uuid, "00000000-0000-0000-0000-000000000000");
@@ -238,8 +238,8 @@
 
 // Test use of compact to merge two databases.
 DEFINE_TESTCASE(compactmerge1, compact) {
-    string indbpath = get_database_path("apitest_simpledata");
-    string outdbpath = get_compaction_output_path("compactmerge1out");
+    std::string indbpath = get_database_path("apitest_simpledata");
+    std::string outdbpath = get_compaction_output_path("compactmerge1out");
     rm_rf(outdbpath);
 
     const string& dbtype = get_dbtype();
@@ -275,7 +275,7 @@
 	    "", "/postlist", "/termlist.", nullptr
 	};
 	for (auto s : suffixes) {
-	    string suffix;
+	    std::string suffix;
 	    if (s) {
 		suffix = s;
 	    } else {
@@ -287,7 +287,7 @@
 	    }
 	    tout.str(string());
 	    tout << "Trying suffix '" << suffix << "'" << endl;
-	    string arg = outdbpath;
+	    std::string arg = outdbpath;
 	    arg += suffix;
 	    TEST_EQUAL(Xapian::Database::check(arg, 0, &tout), 0);
 	}
@@ -295,7 +295,7 @@
 }
 
 static void
-make_multichunk_db(Xapian::WritableDatabase &db, const string &)
+make_multichunk_db(Xapian::WritableDatabase &db, const std::string &)
 {
     int count = 10000;
 
@@ -312,9 +312,9 @@
 // Test use of compact on a database which has multiple chunks for a term.
 // This is a regression test for ticket #427
 DEFINE_TESTCASE(compactmultichunks1, compact && generated) {
-    string indbpath = get_database_path("compactmultichunks1in",
+    std::string indbpath = get_database_path("compactmultichunks1in",
 					make_multichunk_db, "");
-    string outdbpath = get_compaction_output_path("compactmultichunks1out");
+    std::string outdbpath = get_compaction_output_path("compactmultichunks1out");
     rm_rf(outdbpath);
 
     {
@@ -341,7 +341,7 @@
     stub << "auto ../../" << get_database_path("apitest_simpledata2") << endl;
     stub.close();
 
-    string outdbpath = get_compaction_output_path("compactstub1out");
+    std::string outdbpath = get_compaction_output_path("compactstub1out");
     rm_rf(outdbpath);
 
     {
@@ -366,7 +366,7 @@
     stub << "auto ../" << get_database_path("apitest_simpledata2") << endl;
     stub.close();
 
-    string outdbpath = get_compaction_output_path("compactstub2out");
+    std::string outdbpath = get_compaction_output_path("compactstub2out");
     rm_rf(outdbpath);
 
     {
@@ -430,7 +430,7 @@
 }
 
 static void
-make_all_tables(Xapian::WritableDatabase &db, const string &)
+make_all_tables(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("foo");
@@ -443,7 +443,7 @@
 }
 
 static void
-make_missing_tables(Xapian::WritableDatabase &db, const string &)
+make_missing_tables(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("foo");
@@ -453,12 +453,12 @@
 }
 
 DEFINE_TESTCASE(compactmissingtables1, compact && generated) {
-    string a = get_database_path("compactmissingtables1a",
+    std::string a = get_database_path("compactmissingtables1a",
 				 make_all_tables);
-    string b = get_database_path("compactmissingtables1b",
+    std::string b = get_database_path("compactmissingtables1b",
 				 make_missing_tables);
 
-    string out = get_compaction_output_path("compactmissingtables1out");
+    std::string out = get_compaction_output_path("compactmissingtables1out");
     rm_rf(out);
 
     {
@@ -478,7 +478,7 @@
 }
 
 static void
-make_all_tables2(Xapian::WritableDatabase &db, const string &)
+make_all_tables2(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("bar");
@@ -493,12 +493,12 @@
 
 /// Adds coverage for merging synonym table.
 DEFINE_TESTCASE(compactmergesynonym1, compact && generated) {
-    string a = get_database_path("compactmergesynonym1a",
+    std::string a = get_database_path("compactmergesynonym1a",
 				 make_all_tables);
-    string b = get_database_path("compactmergesynonym1b",
+    std::string b = get_database_path("compactmergesynonym1b",
 				 make_all_tables2);
 
-    string out = get_compaction_output_path("compactmergesynonym1out");
+    std::string out = get_compaction_output_path("compactmergesynonym1out");
     rm_rf(out);
 
     {
@@ -538,8 +538,8 @@
 }
 
 DEFINE_TESTCASE(compactempty1, compact) {
-    string empty_dbpath = get_database_path(string());
-    string outdbpath = get_compaction_output_path("compactempty1out");
+    std::string empty_dbpath = get_database_path(string());
+    std::string outdbpath = get_compaction_output_path("compactempty1out");
     rm_rf(outdbpath);
 
     {
@@ -567,16 +567,16 @@
 }
 
 DEFINE_TESTCASE(compactmultipass1, compact && generated) {
-    string outdbpath = get_compaction_output_path("compactmultipass1");
+    std::string outdbpath = get_compaction_output_path("compactmultipass1");
     rm_rf(outdbpath);
 
-    string a = get_database_path("compactnorenumber1a", make_sparse_db,
+    std::string a = get_database_path("compactnorenumber1a", make_sparse_db,
 				 "5-7 24 76 987 1023-1027 9999 !9999");
-    string b = get_database_path("compactnorenumber1b", make_sparse_db,
+    std::string b = get_database_path("compactnorenumber1b", make_sparse_db,
 				 "1027-1030");
-    string c = get_database_path("compactnorenumber1c", make_sparse_db,
+    std::string c = get_database_path("compactnorenumber1c", make_sparse_db,
 				 "1028-1040");
-    string d = get_database_path("compactnorenumber1d", make_sparse_db,
+    std::string d = get_database_path("compactnorenumber1d", make_sparse_db,
 				 "3000 999999 !999999");
 
     {
@@ -596,7 +596,7 @@
 // Chert doesn't support single file databases.
 DEFINE_TESTCASE(compacttofd1, compact && !chert) {
     Xapian::Database indb(get_database("apitest_simpledata"));
-    string outdbpath = get_compaction_output_path("compacttofd1out");
+    std::string outdbpath = get_compaction_output_path("compacttofd1out");
     rm_rf(outdbpath);
 
     int fd = open(outdbpath.c_str(), O_CREAT|O_RDWR|O_BINARY, 0666);
@@ -623,7 +623,7 @@
 // Chert doesn't support single file databases.
 DEFINE_TESTCASE(compacttofd2, compact && !chert) {
     Xapian::Database indb(get_database("apitest_simpledata"));
-    string outdbpath = get_compaction_output_path("compacttofd2out");
+    std::string outdbpath = get_compaction_output_path("compacttofd2out");
     rm_rf(outdbpath);
 
     int fd = open(outdbpath.c_str(), O_CREAT|O_RDWR|O_BINARY, 0666);
@@ -683,7 +683,7 @@
     // Also test a completely empty document.
     db.add_document(Xapian::Document());
 
-    string output = get_compaction_output_path("compactsingle1-out");
+    std::string output = get_compaction_output_path("compactsingle1-out");
     // In 1.3.4, we would hang if the output file already existed, so check
     // that works.
     touch(output);
@@ -721,7 +721,7 @@
     // Also test a completely empty document.
     db.add_document(Xapian::Document());
 
-    string output = get_compaction_output_path("compact1-out");
+    std::string output = get_compaction_output_path("compact1-out");
     rm_rf(output);
 
     TEST_EXCEPTION(Xapian::InvalidOperationError,
diff -ur xapian-core-1.4.21/tests/api_compactold.cc xapian-core-1.4.21/tests/api_compactold.cc
--- xapian-core-1.4.21/tests/api_compactold.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_compactold.cc	2022-11-08 16:44:15.540461287 +0100
@@ -42,7 +42,7 @@
 using namespace std;
 
 static void
-make_sparse_db(Xapian::WritableDatabase &db, const string & s)
+make_sparse_db(Xapian::WritableDatabase &db, const std::string & s)
 {
     // Need non-const pointer for strtoul(), but data isn't modified.
     char * p = const_cast<char *>(s.c_str());
@@ -68,7 +68,7 @@
 		db.delete_document(first);
 	    } else {
 		Xapian::Document doc;
-		string id = str(first);
+		std::string id = str(first);
 		doc.set_data(id);
 		doc.add_term("Q" + str(first));
 		doc.add_term(string(first % 7 + 1, char((first % 26) + 'a')));
@@ -84,7 +84,7 @@
 }
 
 static void
-check_sparse_uid_terms(const string & path)
+check_sparse_uid_terms(const std::string & path)
 {
     Xapian::Database db(path);
     Xapian::TermIterator t;
@@ -97,21 +97,21 @@
 
 // With multi the docids in the shards change the behaviour.
 DEFINE_TESTCASE(compactoldnorenumber1, compact && generated && !multi) {
-    string a = get_database_path("compactnorenumber1a", make_sparse_db,
+    std::string a = get_database_path("compactnorenumber1a", make_sparse_db,
 				 "5-7 24 76 987 1023-1027 9999 !9999");
-    string a_uuid;
+    std::string a_uuid;
     {
 	Xapian::Database db(a);
 	a_uuid = db.get_uuid();
     }
-    string b = get_database_path("compactnorenumber1b", make_sparse_db,
+    std::string b = get_database_path("compactnorenumber1b", make_sparse_db,
 				 "1027-1030");
-    string c = get_database_path("compactnorenumber1c", make_sparse_db,
+    std::string c = get_database_path("compactnorenumber1c", make_sparse_db,
 				 "1028-1040");
-    string d = get_database_path("compactnorenumber1d", make_sparse_db,
+    std::string d = get_database_path("compactnorenumber1d", make_sparse_db,
 				 "3000 999999 !999999");
 
-    string out = get_compaction_output_path("compactnorenumber1out");
+    std::string out = get_compaction_output_path("compactnorenumber1out");
 
     rm_rf(out);
     {
@@ -129,7 +129,7 @@
 	Xapian::Database db(out);
 	// xapian-compact should change the UUID of the database, but didn't
 	// prior to 1.0.18/1.1.4.
-	string out_uuid = db.get_uuid();
+	std::string out_uuid = db.get_uuid();
 	TEST_NOT_EQUAL(a_uuid, out_uuid);
 	TEST_EQUAL(out_uuid.size(), 36);
 	TEST_NOT_EQUAL(out_uuid, "00000000-0000-0000-0000-000000000000");
@@ -241,8 +241,8 @@
 
 // Test use of compact to merge two databases.
 DEFINE_TESTCASE(compactoldmerge1, compact) {
-    string indbpath = get_database_path("apitest_simpledata");
-    string outdbpath = get_compaction_output_path("compactmerge1out");
+    std::string indbpath = get_database_path("apitest_simpledata");
+    std::string outdbpath = get_compaction_output_path("compactmerge1out");
     rm_rf(outdbpath);
 
     Xapian::Compactor compact;
@@ -259,7 +259,7 @@
 }
 
 static void
-make_multichunk_db(Xapian::WritableDatabase &db, const string &)
+make_multichunk_db(Xapian::WritableDatabase &db, const std::string &)
 {
     int count = 10000;
 
@@ -276,9 +276,9 @@
 // Test use of compact on a database which has multiple chunks for a term.
 // This is a regression test for ticket #427
 DEFINE_TESTCASE(compactoldmultichunks1, compact && generated) {
-    string indbpath = get_database_path("compactmultichunks1in",
+    std::string indbpath = get_database_path("compactmultichunks1in",
 					make_multichunk_db, "");
-    string outdbpath = get_compaction_output_path("compactmultichunks1out");
+    std::string outdbpath = get_compaction_output_path("compactmultichunks1out");
     rm_rf(outdbpath);
 
     Xapian::Compactor compact;
@@ -305,7 +305,7 @@
     stub << "auto ../../" << get_database_path("apitest_simpledata2") << endl;
     stub.close();
 
-    string outdbpath = get_compaction_output_path("compactstub1out");
+    std::string outdbpath = get_compaction_output_path("compactstub1out");
     rm_rf(outdbpath);
 
     Xapian::Compactor compact;
@@ -330,7 +330,7 @@
     stub << "auto ../" << get_database_path("apitest_simpledata2") << endl;
     stub.close();
 
-    string outdbpath = get_compaction_output_path("compactstub2out");
+    std::string outdbpath = get_compaction_output_path("compactstub2out");
     rm_rf(outdbpath);
 
     Xapian::Compactor compact;
@@ -402,7 +402,7 @@
 }
 
 static void
-make_all_tables(Xapian::WritableDatabase &db, const string &)
+make_all_tables(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("foo");
@@ -415,7 +415,7 @@
 }
 
 static void
-make_missing_tables(Xapian::WritableDatabase &db, const string &)
+make_missing_tables(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("foo");
@@ -425,12 +425,12 @@
 }
 
 DEFINE_TESTCASE(compactoldmissingtables1, compact && generated) {
-    string a = get_database_path("compactmissingtables1a",
+    std::string a = get_database_path("compactmissingtables1a",
 				 make_all_tables);
-    string b = get_database_path("compactmissingtables1b",
+    std::string b = get_database_path("compactmissingtables1b",
 				 make_missing_tables);
 
-    string out = get_compaction_output_path("compactmissingtables1out");
+    std::string out = get_compaction_output_path("compactmissingtables1out");
     rm_rf(out);
 
     Xapian::Compactor compact;
@@ -449,7 +449,7 @@
 }
 
 static void
-make_all_tables2(Xapian::WritableDatabase &db, const string &)
+make_all_tables2(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_term("bar");
@@ -464,12 +464,12 @@
 
 /// Adds coverage for merging synonym table.
 DEFINE_TESTCASE(compactoldmergesynonym1, compact && generated) {
-    string a = get_database_path("compactmergesynonym1a",
+    std::string a = get_database_path("compactmergesynonym1a",
 				 make_all_tables);
-    string b = get_database_path("compactmergesynonym1b",
+    std::string b = get_database_path("compactmergesynonym1b",
 				 make_all_tables2);
 
-    string out = get_compaction_output_path("compactmergesynonym1out");
+    std::string out = get_compaction_output_path("compactmergesynonym1out");
     rm_rf(out);
 
     Xapian::Compactor compact;
@@ -508,8 +508,8 @@
 }
 
 DEFINE_TESTCASE(compactoldempty1, compact) {
-    string empty_dbpath = get_database_path(string());
-    string outdbpath = get_compaction_output_path("compactempty1out");
+    std::string empty_dbpath = get_database_path(string());
+    std::string outdbpath = get_compaction_output_path("compactempty1out");
     rm_rf(outdbpath);
 
     {
@@ -539,16 +539,16 @@
 }
 
 DEFINE_TESTCASE(compactoldmultipass1, compact && generated) {
-    string outdbpath = get_compaction_output_path("compactmultipass1");
+    std::string outdbpath = get_compaction_output_path("compactmultipass1");
     rm_rf(outdbpath);
 
-    string a = get_database_path("compactnorenumber1a", make_sparse_db,
+    std::string a = get_database_path("compactnorenumber1a", make_sparse_db,
 				 "5-7 24 76 987 1023-1027 9999 !9999");
-    string b = get_database_path("compactnorenumber1b", make_sparse_db,
+    std::string b = get_database_path("compactnorenumber1b", make_sparse_db,
 				 "1027-1030");
-    string c = get_database_path("compactnorenumber1c", make_sparse_db,
+    std::string c = get_database_path("compactnorenumber1c", make_sparse_db,
 				 "1028-1040");
-    string d = get_database_path("compactnorenumber1d", make_sparse_db,
+    std::string d = get_database_path("compactnorenumber1d", make_sparse_db,
 				 "3000 999999 !999999");
 
     Xapian::Compactor compact;
diff -ur xapian-core-1.4.21/tests/api_db.cc xapian-core-1.4.21/tests/api_db.cc
--- xapian-core-1.4.21/tests/api_db.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_db.cc	2022-11-08 16:44:15.500461429 +0100
@@ -47,7 +47,7 @@
 using namespace std;
 
 static Xapian::Query
-query(const string &t)
+query(const std::string &t)
 {
     return Xapian::Query(Xapian::Stem("english")(t));
 }
@@ -191,7 +191,7 @@
 	//  NetworkError: Couldn't resolve host ::1 (context: remote:tcp(::1:65535)) (nodename nor servname provided, or not known)
 	// or on macOS (EAI_NONAME):
 	//  NetworkError: Couldn't resolve host ::1 (context: remote:tcp(::1:65535)) (Address family for hostname not supported)
-	// So we test the message instead of the error string for portability.
+	// So we test the message instead of the error std::string for portability.
 	//
 	// But NetBSD seems to resolve ::1 to an IPv4 address and then tries
 	// to connect to it (which hopefully fails), so just test the message
@@ -495,7 +495,7 @@
 #endif
 
 class GrepMatchDecider : public Xapian::MatchDecider {
-    string needle;
+    std::string needle;
   public:
     explicit GrepMatchDecider(const string& needle_)
 	: needle(needle_) {}
@@ -516,7 +516,7 @@
 
     Xapian::MSet mymset = enquire.get_mset(0, 100, 0, &myfunctor);
 
-    vector<bool> docid_checked(db.get_lastdocid());
+    std::vector<bool> docid_checked(db.get_lastdocid());
 
     // Check that we get the expected number of matches, and that they
     // satisfy the condition.
@@ -643,7 +643,7 @@
 
     Xapian::MSet mymset = enquire.get_mset(0, 100, 0, NULL, &myfunctor);
 
-    vector<bool> docid_checked(db.get_lastdocid());
+    std::vector<bool> docid_checked(db.get_lastdocid());
 
     // Check that we get the expected number of matches, and that they
     // satisfy the condition.
@@ -867,10 +867,10 @@
 	TEST_AND_EXPLAIN(mymsize1 > mymset.size(),
 			 "Had no fewer items when performing collapse: don't know whether it worked.");
 
-	map<string, Xapian::docid> values;
+	std::map<string, Xapian::docid> values;
 	Xapian::MSetIterator i = mymset.begin();
 	for ( ; i != mymset.end(); ++i) {
-	    string value = i.get_document().get_value(value_no);
+	    std::string value = i.get_document().get_value(value_no);
 	    TEST(values[value] == 0 || value.empty());
 	    values[value] = *i;
 	}
@@ -918,10 +918,10 @@
 	TEST_AND_EXPLAIN(mymset1.get_matches_upper_bound() > mymset.get_matches_upper_bound(),
 			 "Upper bound was not lower when performing collapse: don't know whether it worked.");
 
-	map<string, Xapian::docid> values;
+	std::map<string, Xapian::docid> values;
 	Xapian::MSetIterator i = mymset.begin();
 	for ( ; i != mymset.end(); ++i) {
-	    string value = i.get_document().get_value(value_no);
+	    std::string value = i.get_document().get_value(value_no);
 	    TEST(values[value] == 0 || value.empty());
 	    values[value] = *i;
 	}
@@ -940,10 +940,10 @@
 	TEST(mymset.get_matches_lower_bound() <= mymset1.get_matches_lower_bound());
 	TEST_EQUAL(mymset.get_matches_upper_bound(), mymset1.get_matches_upper_bound());
 
-	map<string, Xapian::docid> values;
+	std::map<string, Xapian::docid> values;
 	Xapian::MSetIterator i = mymset.begin();
 	for ( ; i != mymset.end(); ++i) {
-	    string value = i.get_document().get_value(value_no);
+	    std::string value = i.get_document().get_value(value_no);
 	    TEST(values[value] == 0 || value.empty());
 	    values[value] = *i;
 	}
@@ -967,10 +967,10 @@
 	TEST_AND_EXPLAIN(mymset1.get_matches_upper_bound() == mymset.get_matches_upper_bound(),
 			 "Upper bound was changed when performing collapse but not asking for any results.");
 
-	map<string, Xapian::docid> values;
+	std::map<string, Xapian::docid> values;
 	Xapian::MSetIterator i = mymset.begin();
 	for ( ; i != mymset.end(); ++i) {
-	    string value = i.get_document().get_value(value_no);
+	    std::string value = i.get_document().get_value(value_no);
 	    TEST(values[value] == 0 || value.empty());
 	    values[value] = *i;
 	}
@@ -1182,7 +1182,7 @@
     TEST_EQUAL(count, 1);
 
     for (Xapian::valueno value_no = 0; value_no < 7; ++value_no) {
-	string value = mymset.begin().get_document().get_value(value_no);
+	std::string value = mymset.begin().get_document().get_value(value_no);
 	TEST_NOT_EQUAL(value, "");
 	if (value_no == 0) {
 	    TEST(value.size() > 263);
@@ -1324,7 +1324,7 @@
 
     TEST_EQUAL(db.postlist_begin("rosebud"), db.postlist_end("rosebud"));
 
-    string s = "let_us_see_if_we_can_break_it_with_a_really_really_long_term.";
+    std::string s = "let_us_see_if_we_can_break_it_with_a_really_really_long_term.";
     for (int i = 0; i < 8; ++i) {
 	s += s;
 	TEST_EQUAL(db.postlist_begin(s), db.postlist_end(s));
@@ -1355,11 +1355,11 @@
 
     TEST(p_clone.get_description() != "PostingIterator()");
 
-    vector<Xapian::docid> v(p, pend);
+    std::vector<Xapian::docid> v(p, pend);
 
     p = db.postlist_begin("this");
     pend = db.postlist_end("this");
-    vector<Xapian::docid>::const_iterator i;
+    std::vector<Xapian::docid>::const_iterator i;
     for (i = v.begin(); i != v.end(); ++i) {
 	TEST_NOT_EQUAL(p, pend);
 	TEST_EQUAL(*i, *p);
@@ -1618,7 +1618,7 @@
     TEST_EXCEPTION(Xapian::DatabaseNotFoundError,
 	    Xapian::WritableDatabase("no/such/directory", Xapian::DB_OPEN));
 
-    string empty_dir = "emptydirectory";
+    std::string empty_dir = "emptydirectory";
     mkdir(empty_dir.c_str(), 0700);
     TEST_EXCEPTION(Xapian::DatabaseNotFoundError,
 	    Xapian::Database{empty_dir});
@@ -1627,7 +1627,7 @@
 /// Test opening of a chert database
 DEFINE_TESTCASE(chertdatabaseopen1, chert) {
 #ifdef XAPIAN_HAS_CHERT_BACKEND
-    const string dbdir = ".chert/test_chertdatabaseopen1";
+    const std::string dbdir = ".chert/test_chertdatabaseopen1";
     mkdir(".chert", 0755);
 
     {
@@ -1881,7 +1881,7 @@
 	TEST_EQUAL(mset.get_max_attained(), 1.445962071042388164);
 	TEST_EQUAL(mset.size(), 7);
 
-	static const pair<Xapian::docid, double> to_compare[] = {
+	static const std::pair<Xapian::docid, double> to_compare[] = {
 	    {7, 1.445962071042388164},
 	    {3, 1.4140112748017070743},
 	    {1, 1.3747698831232337824},
@@ -1909,8 +1909,8 @@
     MyWeight() { }
     ~MyWeight() { }
     std::string name() const { return "MyWeight"; }
-    string serialise() const { return string(); }
-    MyWeight * unserialise(const string &) const { return new MyWeight; }
+    std::string serialise() const { return string(); }
+    MyWeight * unserialise(const std::string &) const { return new MyWeight; }
     double get_sumpart(Xapian::termcount, Xapian::termcount, Xapian::termcount) const {
 	return scale_factor;
     }
diff -ur xapian-core-1.4.21/tests/api_geospatial.cc xapian-core-1.4.21/tests/api_geospatial.cc
--- xapian-core-1.4.21/tests/api_geospatial.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_geospatial.cc	2022-11-08 16:44:15.552461245 +0100
@@ -36,7 +36,7 @@
 // # Tests start here
 
 static void
-builddb_coords1(Xapian::WritableDatabase &db, const string &)
+builddb_coords1(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::LatLongCoord coord1(10, 10);
     Xapian::LatLongCoord coord2(20, 10);
@@ -370,8 +370,8 @@
     LatLongCoord c2(1, 0);
     LatLongCoords cl1(c1);
     LatLongCoords cl2(c2);
-    string c2_str = c2.serialise();
-    string cl2_str = cl2.serialise();
+    std::string c2_str = c2.serialise();
+    std::string cl2_str = cl2.serialise();
     TEST_EQUAL(c2_str, cl2_str);
 
     LatLongCoord c2_check(5, 5);
diff -ur xapian-core-1.4.21/tests/api_matchspy.cc xapian-core-1.4.21/tests/api_matchspy.cc
--- xapian-core-1.4.21/tests/api_matchspy.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_matchspy.cc	2022-11-08 16:44:15.504461416 +0100
@@ -70,7 +70,7 @@
     // Check that the match estimates aren't affected by the matchspy.
     TEST_EQUAL(nospymset, spymset);
 
-    vector<bool> docid_checked(db.get_lastdocid());
+    std::vector<bool> docid_checked(db.get_lastdocid());
 
     // Check that we get the expected number of matches, and that the stored
     // document contents are right.
@@ -96,8 +96,8 @@
     }
 }
 
-static string values_to_repr(const Xapian::ValueCountMatchSpy & spy) {
-    string resultrepr("|");
+static std::string values_to_repr(const Xapian::ValueCountMatchSpy & spy) {
+    std::string resultrepr("|");
     for (Xapian::TermIterator i = spy.values_begin();
 	 i != spy.values_end();
 	 ++i) {
@@ -110,7 +110,7 @@
 }
 
 static void
-make_matchspy2_db(Xapian::WritableDatabase &db, const string &)
+make_matchspy2_db(Xapian::WritableDatabase &db, const std::string &)
 {
     for (int c = 1; c <= 25; ++c) {
 	Xapian::Document doc;
@@ -244,7 +244,7 @@
     for (Xapian::valueno v = 0; results[v]; ++v) {
 	tout << "value " << v << endl;
 	Xapian::ValueCountMatchSpy * spy = spies[v];
-	string allvals_str("|");
+	std::string allvals_str("|");
 	if (spy != NULL) {
 	    size_t allvals_size = 0;
 	    for (Xapian::TermIterator i = spy->top_values_begin(100);
@@ -337,7 +337,7 @@
 DEFINE_TESTCASE(matchspy7, !backend)
 {
     Xapian::ValueCountMatchSpy myspy(1);
-    string s = myspy.serialise_results();
+    std::string s = myspy.serialise_results();
     s += 'x';
     // This merge_results() call used to enter an infinite loop.
     TEST_EXCEPTION(Xapian::NetworkError, myspy.merge_results(s));
diff -ur xapian-core-1.4.21/tests/api_metadata.cc xapian-core-1.4.21/tests/api_metadata.cc
--- xapian-core-1.4.21/tests/api_metadata.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_metadata.cc	2022-11-08 16:44:15.504461416 +0100
@@ -261,9 +261,9 @@
 DEFINE_TESTCASE(writeread1, writable && metadata) {
     Xapian::WritableDatabase db_w = get_writable_database();
     db_w.set_metadata("1", "2");
-    string longitem(20000, 'j');
+    std::string longitem(20000, 'j');
     db_w.set_metadata("2", longitem);
 
-    string readitem = db_w.get_metadata("2");
+    std::string readitem = db_w.get_metadata("2");
     TEST_EQUAL(readitem, longitem);
 }
diff -ur xapian-core-1.4.21/tests/api_nodb.cc xapian-core-1.4.21/tests/api_nodb.cc
--- xapian-core-1.4.21/tests/api_nodb.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_nodb.cc	2022-11-08 16:44:15.532461315 +0100
@@ -45,7 +45,7 @@
 
 // tests that get_query_terms() returns the terms in the right order
 DEFINE_TESTCASE(getqterms1, !backend) {
-    list<string> answers_list;
+    std::list<string> answers_list;
     answers_list.push_back("one");
     answers_list.push_back("two");
     answers_list.push_back("three");
@@ -59,14 +59,14 @@
 		    Xapian::Query("four", 1, 4),
 		    Xapian::Query("two", 1, 2)));
 
-    list<string> list1;
+    std::list<string> list1;
     {
 	Xapian::TermIterator t;
 	for (t = myquery.get_terms_begin(); t != myquery.get_terms_end(); ++t)
 	    list1.push_back(*t);
     }
     TEST(list1 == answers_list);
-    list<string> list2(myquery.get_terms_begin(), myquery.get_terms_end());
+    std::list<string> list2(myquery.get_terms_begin(), myquery.get_terms_end());
     TEST(list2 == answers_list);
 }
 
@@ -85,7 +85,7 @@
     TEST(Xapian::Query().empty());
     // test that an empty query has length 0
     TEST(Xapian::Query().get_length() == 0);
-    vector<Xapian::Query> v;
+    std::vector<Xapian::Query> v;
     TEST(Xapian::Query(Xapian::Query::OP_OR, v.begin(), v.end()).empty());
     TEST(Xapian::Query(Xapian::Query::OP_OR, v.begin(), v.end()).get_length() == 0);
 }
@@ -133,7 +133,7 @@
 // tests that query lengths are calculated correctly
 DEFINE_TESTCASE(querylen2, !backend) {
     // test with an even bigger and strange query
-    string terms[3] = {
+    std::string terms[3] = {
 	"foo",
 	"bar",
 	"baz"
@@ -145,9 +145,9 @@
     };
 
     Xapian::Query myquery;
-    vector<string> v1(terms, terms + 3);
-    vector<Xapian::Query> v2(queries, queries + 3);
-    vector<Xapian::Query *> v3;
+    std::vector<string> v1(terms, terms + 3);
+    std::vector<Xapian::Query> v2(queries, queries + 3);
+    std::vector<Xapian::Query *> v3;
     Xapian::Query query1(Xapian::Query::OP_AND, string("ball"), string("club"));
     Xapian::Query query2("ring");
     v3.push_back(&query1);
@@ -199,12 +199,12 @@
 	Xapian::Query("wobble")
     };
 
-    vector<Xapian::Query> vec1(queries1, queries1 + 3);
+    std::vector<Xapian::Query> vec1(queries1, queries1 + 3);
     Xapian::Query myquery1(Xapian::Query::OP_OR, vec1.begin(), vec1.end());
     TEST_EQUAL(myquery1.get_description(),
 	       "Query((wibble OR wobble OR (jelly OR belly)))");
 
-    vector<Xapian::Query> vec2(queries2, queries2 + 3);
+    std::vector<Xapian::Query> vec2(queries2, queries2 + 3);
     Xapian::Query myquery2(Xapian::Query::OP_AND, vec2.begin(), vec2.end());
     TEST_EQUAL(myquery2.get_description(),
 	       "Query(((jelly AND belly) AND wibble AND wobble))");
@@ -212,7 +212,7 @@
 
 // test behaviour when creating a query from an empty vector
 DEFINE_TESTCASE(emptyquerypart1, !backend) {
-    vector<string> emptyterms;
+    std::vector<string> emptyterms;
     Xapian::Query query(Xapian::Query::OP_OR, emptyterms.begin(), emptyterms.end());
     TEST(Xapian::Query(Xapian::Query::OP_AND, query, Xapian::Query("x")).empty());
     TEST(Xapian::Query(Xapian::Query::OP_AND, query, Xapian::Query("x")).get_length() == 0);
@@ -221,7 +221,7 @@
 }
 
 DEFINE_TESTCASE(stemlangs1, !backend) {
-    string langs = Xapian::Stem::get_available_languages();
+    std::string langs = Xapian::Stem::get_available_languages();
     tout << "available languages '" << langs << "'" << endl;
     TEST(!langs.empty());
 
@@ -238,12 +238,12 @@
 
 	// Try making a stemmer for this language.  We should be able to create
 	// it without an exception being thrown.
-	string language(langs, i, spc - i);
+	std::string language(langs, i, spc - i);
 	tout << "checking language code '" << language << "' works" << endl;
 	Xapian::Stem stemmer(language);
 	TEST(!stemmer.is_none());
 	if (language.size() > 2) {
-	    string expected("Xapian::Stem(");
+	    std::string expected("Xapian::Stem(");
 	    expected += language;
 	    expected += ')';
 	    TEST_EQUAL(stemmer.get_description(), expected);
@@ -545,7 +545,7 @@
 }
 
 DEFINE_TESTCASE(expanddeciderfilterprefix1, !backend) {
-    string prefix = "tw";
+    std::string prefix = "tw";
     Xapian::ExpandDeciderFilterPrefix decider(prefix);
     TEST(!decider("one"));
     TEST(!decider("t"));
diff -ur xapian-core-1.4.21/tests/api_none.cc xapian-core-1.4.21/tests/api_none.cc
--- xapian-core-1.4.21/tests/api_none.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_none.cc	2022-11-08 16:44:15.504461416 +0100
@@ -36,7 +36,7 @@
 
 // Check the version functions give consistent results.
 DEFINE_TESTCASE(version1, !backend) {
-    string version = str(Xapian::major_version());
+    std::string version = str(Xapian::major_version());
     version += '.';
     version += str(Xapian::minor_version());
     version += '.';
@@ -348,7 +348,7 @@
   public:
     TestFieldProcessor(bool & destroyed_) : destroyed(destroyed_) { }
 
-    Xapian::Query operator()(const string &str) {
+    Xapian::Query operator()(const std::string &str) {
 	return Xapian::Query(str);
     }
 };
@@ -625,7 +625,7 @@
   public:
     TestKeyMaker(bool & destroyed_) : destroyed(destroyed_) { }
 
-    string operator()(const Xapian::Document&) const { return string(); }
+    std::string operator()(const Xapian::Document&) const { return string(); }
 };
 
 /// Check reference counting of KeyMaker.
diff -ur xapian-core-1.4.21/tests/api_opsynonym.cc xapian-core-1.4.21/tests/api_opsynonym.cc
--- xapian-core-1.4.21/tests/api_opsynonym.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_opsynonym.cc	2022-11-08 16:44:15.524461344 +0100
@@ -256,8 +256,8 @@
 	TEST_NOT_EQUAL(synmset.size(), 0);
 	// Check that the queries return the same number of results.
 	TEST_EQUAL(synmset.size(), ormset.size());
-	map<Xapian::docid, double> values_or;
-	map<Xapian::docid, double> values_synonym;
+	std::map<Xapian::docid, double> values_or;
+	std::map<Xapian::docid, double> values_synonym;
 	for (Xapian::doccount i = 0; i < synmset.size(); ++i) {
 	    values_or[*ormset[i]] = ormset[i].get_weight();
 	    values_synonym[*synmset[i]] = synmset[i].get_weight();
@@ -268,7 +268,7 @@
 	 * different from those in the "synonym" mset. */
 	int same_weight = 0;
 	int different_weight = 0;
-	for (map<Xapian::docid, double>::const_iterator
+	for (std::map<Xapian::docid, double>::const_iterator
 	     j = values_or.begin(); j != values_or.end(); ++j) {
 	    Xapian::docid did = j->first;
 	    // Check that all the results in the or tree make it to the synonym
@@ -296,7 +296,7 @@
 // Regression test - test a synonym search with a MultiAndPostlist.
 DEFINE_TESTCASE(synonym2, backend) {
     Xapian::Query query;
-    vector<Xapian::Query> subqueries;
+    std::vector<Xapian::Query> subqueries;
     subqueries.push_back(Xapian::Query("file"));
     subqueries.push_back(Xapian::Query("the"));
     subqueries.push_back(Xapian::Query("next"));
@@ -441,13 +441,13 @@
 
     // Check that the weights in msetmax are the maximum of the weights in
     // mset1 and mset2 for each docid.
-    map<Xapian::docid, double> expected_weights;
+    std::map<Xapian::docid, double> expected_weights;
     Xapian::MSetIterator i;
     for (i = mset1.begin(); i != mset1.end(); ++i) {
 	expected_weights[*i] = i.get_weight();
     }
     for (i = mset2.begin(); i != mset2.end(); ++i) {
-	map<Xapian::docid, double>::iterator j;
+	std::map<Xapian::docid, double>::iterator j;
 	j = expected_weights.find(*i);
 	if (j != expected_weights.end()) {
 	    j->second = max(j->second, i.get_weight());
@@ -457,7 +457,7 @@
     }
 
     for (i = msetmax.begin(); i != msetmax.end(); ++i) {
-	map<Xapian::docid, double>::iterator j;
+	std::map<Xapian::docid, double>::iterator j;
 	j = expected_weights.find(*i);
 	TEST(j != expected_weights.end());
 	TEST_EQUAL_DOUBLE(j->second, i.get_weight());
diff -ur xapian-core-1.4.21/tests/api_opvalue.cc xapian-core-1.4.21/tests/api_opvalue.cc
--- xapian-core-1.4.21/tests/api_opvalue.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_opvalue.cc	2022-11-08 16:44:15.484461486 +0100
@@ -52,14 +52,14 @@
 	    Xapian::MSetIterator i;
 	    for (i = mset.begin(); i != mset.end(); ++i) {
 		matched.insert(*i);
-		string value = db.get_document(*i).get_value(1);
+		std::string value = db.get_document(*i).get_value(1);
 		TEST_REL(value,>=,start);
 		TEST_REL(value,<=,end);
 	    }
 	    // Check that documents not in the MSet don't match the value range filter.
 	    for (Xapian::docid j = db.get_lastdocid(); j != 0; --j) {
 		if (matched.find(j) == matched.end()) {
-		    string value = db.get_document(j).get_value(1);
+		    std::string value = db.get_document(j).get_value(1);
 		    tout << value << " < '" << start << "' or > '" << end << "'" << endl;
 		    TEST(value < start || value > end);
 		}
@@ -87,7 +87,7 @@
 }
 
 static void
-make_valuerange5(Xapian::WritableDatabase &db, const string &)
+make_valuerange5(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     doc.add_value(0, "BOOK");
@@ -119,7 +119,7 @@
 }
 
 static void
-make_singularvalue_db(Xapian::WritableDatabase &db, const string &)
+make_singularvalue_db(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     db.add_document(doc);
@@ -238,7 +238,7 @@
 }
 
 static void
-make_valprefixbounds_db(Xapian::WritableDatabase &db, const string &)
+make_valprefixbounds_db(Xapian::WritableDatabase &db, const std::string &)
 {
     Xapian::Document doc;
     db.add_document(doc);
@@ -296,7 +296,7 @@
 	Xapian::MSetIterator i;
 	for (i = mset.begin(); i != mset.end(); ++i) {
 	    matched.insert(*i);
-	    string value = db.get_document(*i).get_value(1);
+	    std::string value = db.get_document(*i).get_value(1);
 	    tout << "'" << start << "' <= '" << value << "'" << endl;
 	    TEST_REL(value,>=,start);
 	}
@@ -304,7 +304,7 @@
 	// filter.
 	for (Xapian::docid j = db.get_lastdocid(); j != 0; --j) {
 	    if (matched.find(j) == matched.end()) {
-		string value = db.get_document(j).get_value(1);
+		std::string value = db.get_document(j).get_value(1);
 		tout << value << " < '" << start << "'" << endl;
 		TEST_REL(value,<,start);
 	    }
@@ -340,14 +340,14 @@
 	Xapian::MSetIterator i;
 	for (i = mset.begin(); i != mset.end(); ++i) {
 	    matched.insert(*i);
-	    string value = db.get_document(*i).get_value(1);
+	    std::string value = db.get_document(*i).get_value(1);
 	    TEST_REL(value,<=,end);
 	}
 	// Check that documents not in the MSet don't match the value range
 	// filter.
 	for (Xapian::docid j = db.get_lastdocid(); j != 0; --j) {
 	    if (matched.find(j) == matched.end()) {
-		string value = db.get_document(j).get_value(1);
+		std::string value = db.get_document(j).get_value(1);
 		TEST_REL(value,>,end);
 	    }
 	}
diff -ur xapian-core-1.4.21/tests/api_percentages.cc xapian-core-1.4.21/tests/api_percentages.cc
--- xapian-core-1.4.21/tests/api_percentages.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_percentages.cc	2022-11-08 16:44:15.548461259 +0100
@@ -67,11 +67,11 @@
 }
 
 class MyPostingSource : public Xapian::PostingSource {
-    vector<pair<Xapian::docid, double>> weights;
-    vector<pair<Xapian::docid, double>>::const_iterator i;
+    std::vector<pair<Xapian::docid, double>> weights;
+    std::vector<pair<Xapian::docid, double>>::const_iterator i;
     bool started;
 
-    MyPostingSource(const vector<pair<Xapian::docid, double>>& weights_,
+    MyPostingSource(const std::vector<pair<Xapian::docid, double>>& weights_,
 		    double max_wt)
 	: weights(weights_), started(false)
     {
@@ -114,7 +114,7 @@
 
     Xapian::docid get_docid() const { return i->first; }
 
-    string get_description() const {
+    std::string get_description() const {
 	return "MyPostingSource";
     }
 };
@@ -261,7 +261,7 @@
 }
 
 static void
-make_topercent7_db(Xapian::WritableDatabase &db, const string &)
+make_topercent7_db(Xapian::WritableDatabase &db, const std::string &)
 {
     for (int i = 1; i <= 6; ++i) {
 	Xapian::Document d;
diff -ur xapian-core-1.4.21/tests/api_posdb.cc xapian-core-1.4.21/tests/api_posdb.cc
--- xapian-core-1.4.21/tests/api_posdb.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_posdb.cc	2022-11-08 16:44:15.560461217 +0100
@@ -44,7 +44,7 @@
     enquire.set_weighting_scheme(Xapian::BoolWeight());
 
     // make a query
-    vector<Xapian::Query> subqs;
+    std::vector<Xapian::Query> subqs;
     Xapian::Query q;
     subqs.push_back(Xapian::Query(stemmer("phrase")));
     subqs.push_back(Xapian::Query(stemmer("fridge")));
@@ -183,7 +183,7 @@
     Xapian::MSet mymset;
 
     // make a query
-    vector<Xapian::Query> subqs;
+    std::vector<Xapian::Query> subqs;
     Xapian::Query q;
     subqs.push_back(Xapian::Query(Xapian::Query::OP_AND,
 			    Xapian::Query(stemmer("phrase")),
@@ -233,7 +233,7 @@
     enquire.set_weighting_scheme(Xapian::BoolWeight());
 
     // make a query
-    vector<Xapian::Query> subqs;
+    std::vector<Xapian::Query> subqs;
     Xapian::Query q;
     subqs.push_back(Xapian::Query(stemmer("phrase")));
     subqs.push_back(Xapian::Query(stemmer("fridge")));
@@ -420,7 +420,7 @@
     Xapian::MSet mymset;
 
     // make a query
-    vector<Xapian::Query> subqs;
+    std::vector<Xapian::Query> subqs;
     Xapian::Query q;
     subqs.push_back(Xapian::Query(Xapian::Query::OP_AND,
 			    Xapian::Query(stemmer("phrase")),
@@ -467,7 +467,7 @@
     Xapian::Database mydb(get_database("apitest_poslist"));
 
     Xapian::Stem stemmer("english");
-    string term = stemmer("sponge");
+    std::string term = stemmer("sponge");
 
     Xapian::PositionIterator pli = mydb.positionlist_begin(2, term);
 
diff -ur xapian-core-1.4.21/tests/api_postingsource.cc xapian-core-1.4.21/tests/api_postingsource.cc
--- xapian-core-1.4.21/tests/api_postingsource.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_postingsource.cc	2022-11-08 16:44:15.508461401 +0100
@@ -83,7 +83,7 @@
 
     Xapian::docid get_docid() const { return did; }
 
-    string get_description() const { return "MyOddPostingSource"; }
+    std::string get_description() const { return "MyOddPostingSource"; }
 };
 
 DEFINE_TESTCASE(externalsource1, backend && !remote && !multi) {
@@ -187,7 +187,7 @@
 
     Xapian::docid get_docid() const { return did; }
 
-    string get_description() const {
+    std::string get_description() const {
 	return "MyOddWeightingPostingSource";
     }
 };
@@ -288,7 +288,7 @@
 
     Xapian::docid get_docid() const { return did; }
 
-    string get_description() const {
+    std::string get_description() const {
 	return "MyDontAskWeightPostingSource";
     }
 };
@@ -483,7 +483,7 @@
 
     bool at_end() const { return did >= 5; }
     Xapian::docid get_docid() const { return did; }
-    string get_description() const { return "ChangeMaxweightPostingSource"; }
+    std::string get_description() const { return "ChangeMaxweightPostingSource"; }
 };
 
 // Test a posting source with a variable maxweight.
@@ -607,7 +607,7 @@
 };
 
 static void
-make_matchtimelimit1_db(Xapian::WritableDatabase &db, const string &)
+make_matchtimelimit1_db(Xapian::WritableDatabase &db, const std::string &)
 {
     for (int wt = 20; wt > 0; --wt) {
 	Xapian::Document doc;
@@ -715,7 +715,7 @@
 
     Xapian::docid get_docid() const { return 0; }
 
-    string get_description() const { return "CloneTestPostingSource"; }
+    std::string get_description() const { return "CloneTestPostingSource"; }
 };
 
 /// Test cloning of initial object, which regressed in 1.3.5.
@@ -792,7 +792,7 @@
 
     Xapian::docid get_docid() const { return did; }
 
-    string get_description() const { return "OnlyTheFirstPostingSource"; }
+    std::string get_description() const { return "OnlyTheFirstPostingSource"; }
 };
 
 Xapian::doccount OnlyTheFirstPostingSource::shard_index;
@@ -861,7 +861,7 @@
 	FAIL_TEST("EstimatePS::get_docid() shouldn't be called");
     }
 
-    string get_description() const { return "EstimatePS"; }
+    std::string get_description() const { return "EstimatePS"; }
 };
 
 /// Check estimate is rounded to suitable number of S.F. - new in 1.4.3.
diff -ur xapian-core-1.4.21/tests/api_qpbackend.cc xapian-core-1.4.21/tests/api_qpbackend.cc
--- xapian-core-1.4.21/tests/api_qpbackend.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_qpbackend.cc	2022-11-08 16:44:15.524461344 +0100
@@ -80,7 +80,7 @@
 
     const test *p;
     for (p = test_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -102,7 +102,7 @@
     }
 
     for (p = test_queries_auto; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -124,7 +124,7 @@
     }
 
     for (p = test_queries_partial_auto; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
diff -ur xapian-core-1.4.21/tests/api_query.cc xapian-core-1.4.21/tests/api_query.cc
--- xapian-core-1.4.21/tests/api_query.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_query.cc	2022-11-08 16:44:15.548461259 +0100
@@ -73,7 +73,7 @@
 DEFINE_TESTCASE(matchnothing1, !backend) {
     TEST_STRINGS_EQUAL(Xapian::Query::MatchNothing.get_description(),
 		       "Query()");
-    vector<Xapian::Query> subqs;
+    std::vector<Xapian::Query> subqs;
     subqs.push_back(Xapian::Query("foo"));
     subqs.push_back(Xapian::Query::MatchNothing);
     Xapian::Query q(Xapian::Query::OP_AND, subqs.begin(), subqs.end());
diff -ur xapian-core-1.4.21/tests/api_queryparser.cc xapian-core-1.4.21/tests/api_queryparser.cc
--- xapian-core-1.4.21/tests/api_queryparser.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_queryparser.cc	2022-11-08 16:44:15.492461458 +0100
@@ -752,7 +752,7 @@
 	    }
 	    FAIL_TEST("Unknown flag code: " << p->expect);
 	}
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -822,7 +822,7 @@
 	    }
 	    FAIL_TEST("Unknown flag code: " << p->expect);
 	}
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -904,7 +904,7 @@
 // Test query with odd characters in.
 DEFINE_TESTCASE(qp_odd_chars1, !backend) {
     Xapian::QueryParser qp;
-    string query("\x01weird\x00stuff\x7f", 13);
+    std::string query("\x01weird\x00stuff\x7f", 13);
     Xapian::Query qobj = qp.parse_query(query);
     tout << "Query:  " << query << '\n';
     TEST_STRINGS_EQUAL(qobj.get_description(), "Query((weird@1 OR stuff@2))"); // FIXME: should these be stemmed?
@@ -1029,7 +1029,7 @@
 static void
 test_qp_flag_wildcard3_helper(const Xapian::Database &db,
 			      Xapian::termcount max_expansion,
-			      const string & query_string)
+			      const std::string & query_string)
 {
     Xapian::QueryParser qp;
     qp.set_database(db);
@@ -1292,7 +1292,7 @@
     qp.set_stopper(&stop);
     qp.set_default_op(Xapian::Query::OP_AND);
     for (const test *p = test_stop_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1328,7 +1328,7 @@
     qp.set_stemmer(Xapian::Stem("english"));
     qp.set_stemming_strategy(QueryParser::STEM_SOME);
     for (const test *p = test_pure_not_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1502,7 +1502,7 @@
     Xapian::StringValueRangeProcessor vrp(1);
     qp.add_valuerangeprocessor(&vrp);
     for (const test *p = test_value_range1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1530,7 +1530,7 @@
     Xapian::RangeProcessor rp(1);
     qp.add_rangeprocessor(&rp);
     for (const test *p = test_value_range1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1600,7 +1600,7 @@
     qp.add_valuerangeprocessor(&vrp_weight);
     qp.add_valuerangeprocessor(&vrp_str);
     for (const test *p = test_value_range2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1638,7 +1638,7 @@
     qp.add_rangeprocessor(&rp_weight);
     qp.add_rangeprocessor(&rp_str);
     for (const test *p = test_value_range2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1681,7 +1681,7 @@
 	double start = low + j * step;
 	for (int k = 0; k <= steps; ++k) {
 	    double end = low + k * step;
-	    string query = str(start) + ".." + str(end);
+	    std::string query = str(start) + ".." + str(end);
 	    tout << "Query: " << query << '\n';
 	    Xapian::Query qobj = qp.parse_query(query);
 	    Xapian::Enquire enq(db);
@@ -1723,7 +1723,7 @@
 	double start = low + j * step;
 	for (int k = 0; k <= steps; ++k) {
 	    double end = low + k * step;
-	    string query = str(start) + ".." + str(end);
+	    std::string query = str(start) + ".." + str(end);
 	    tout << "Query: " << query << '\n';
 	    Xapian::Query qobj = qp.parse_query(query);
 	    Xapian::Enquire enq(db);
@@ -1763,7 +1763,7 @@
     Xapian::StringValueRangeProcessor vrp_str(1, "hello:");
     qp.add_valuerangeprocessor(&vrp_str);
     for (const test *p = test_value_range4_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1797,7 +1797,7 @@
     Xapian::RangeProcessor rp_str(1, "hello:");
     qp.add_rangeprocessor(&rp_str);
     for (const test *p = test_value_range4_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1834,7 +1834,7 @@
     Xapian::DateValueRangeProcessor vrp_date(1, true, 1960);
     qp.add_valuerangeprocessor(&vrp_date);
     for (const test *p = test_value_daterange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1861,7 +1861,7 @@
     Xapian::DateRangeProcessor rp_date(1, Xapian::RP_DATE_PREFER_MDY, 1960);
     qp.add_rangeprocessor(&rp_date);
     for (const test *p = test_value_daterange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1912,7 +1912,7 @@
     qp.add_valuerangeprocessor(&vrp_adate);
     qp.add_valuerangeprocessor(&vrp_ddate);
     for (const test *p = test_value_daterange2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1949,7 +1949,7 @@
     qp.add_rangeprocessor(&rp_adate);
     qp.add_rangeprocessor(&rp_ddate);
     for (const test *p = test_value_daterange2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -1984,7 +1984,7 @@
     qp.add_valuerangeprocessor(&vrp_tag);
     qp.add_valuerangeprocessor(&vrp_default);
     for (const test *p = test_value_stringrange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2013,7 +2013,7 @@
     qp.add_rangeprocessor(&rp_tag);
     qp.add_rangeprocessor(&rp_default);
     for (const test *p = test_value_stringrange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2058,7 +2058,7 @@
     AuthorValueRangeProcessor vrp_author;
     qp.add_valuerangeprocessor(&vrp_author);
     for (const test *p = test_value_customrange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2084,8 +2084,8 @@
 
     Xapian::Query operator()(const std::string& b, const std::string& e)
     {
-	string begin = Xapian::Unicode::tolower(b);
-	string end = Xapian::Unicode::tolower(e);
+	std::string begin = Xapian::Unicode::tolower(b);
+	std::string end = Xapian::Unicode::tolower(e);
 	return Xapian::RangeProcessor::operator()(begin, end);
     }
 };
@@ -2096,7 +2096,7 @@
     AuthorRangeProcessor rp_author;
     qp.add_rangeprocessor(&rp_author);
     for (const test *p = test_value_customrange1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2129,7 +2129,7 @@
     Xapian::Query operator()(const std::string & str) {
 	if (str == "*")
 	    return Xapian::Query::MatchAll;
-	string res = "H";
+	std::string res = "H";
 	for (string::const_iterator i = str.begin(); i != str.end(); ++i)
 	    res += C_tolower(*i);
 	return Xapian::Query(res);
@@ -2153,7 +2153,7 @@
     qp.add_prefix("title", &title_fproc);
     qp.add_boolean_prefix("host", &host_fproc);
     for (const test *p = test_fieldproc1_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2208,7 +2208,7 @@
     Xapian::DateValueRangeProcessor vrp_date(1, "date:");
     qp.add_valuerangeprocessor(&vrp_date);
     for (const test *p = test_fieldproc2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2237,7 +2237,7 @@
     Xapian::DateRangeProcessor rp_date(1, "date:");
     qp.add_rangeprocessor(&rp_date);
     for (const test *p = test_fieldproc2_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2480,7 +2480,7 @@
     qp.set_database(db);
 
     for (const test *p = test_synonym_queries; p->query; ++p) {
-	string expect = "Query(";
+	std::string expect = "Query(";
 	expect += p->expect;
 	expect += ')';
 	Xapian::Query q;
@@ -2516,7 +2516,7 @@
     qp.set_database(db);
 
     for (const test *p = test_multi_synonym_queries; p->query; ++p) {
-	string expect = "Query(";
+	std::string expect = "Query(";
 	expect += p->expect;
 	expect += ')';
 	Xapian::Query q;
@@ -2566,7 +2566,7 @@
     qp.add_prefix("foo", "XFOO");
 
     for (const test *p = test_synonym_op_queries; p->query; ++p) {
-	string expect = "Query(";
+	std::string expect = "Query(";
 	expect += p->expect;
 	expect += ')';
 	Xapian::Query q;
@@ -2594,7 +2594,7 @@
     qp.set_stemming_strategy(qp.STEM_ALL);
     qp.add_prefix("title", "XT");
     for (const test *p = test_stem_all_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2629,7 +2629,7 @@
     qp.set_stemming_strategy(qp.STEM_ALL_Z);
     qp.add_prefix("title", "XT");
     for (const test *p = test_stem_all_z_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2651,7 +2651,7 @@
 }
 
 static double
-time_query_parse(const Xapian::Database & db, const string & q,
+time_query_parse(const Xapian::Database & db, const std::string & q,
 		 int repetitions, unsigned flags)
 {
     Xapian::QueryParser qp;
@@ -2669,7 +2669,7 @@
 }
 
 static void
-qp_scale1_helper(const Xapian::Database &db, const string & q, unsigned n,
+qp_scale1_helper(const Xapian::Database &db, const std::string & q, unsigned n,
 		 unsigned flags)
 {
     double time1;
@@ -2687,7 +2687,7 @@
 
     n /= 5;
 
-    string q_n;
+    std::string q_n;
     q_n.reserve(q.size() * n);
     for (unsigned i = n; i != 0; --i) {
 	q_n += q;
@@ -2710,12 +2710,12 @@
     db.add_synonym("foo", "bar");
     db.commit();
 
-    string q1("foo ");
-    string q1b("baz ");
+    std::string q1("foo ");
+    std::string q1b("baz ");
     const unsigned repetitions = 5000;
 
     // A long multiword synonym.
-    string syn;
+    std::string syn;
     for (int j = 50; j != 0; --j) {
 	syn += q1;
     }
@@ -2792,7 +2792,7 @@
     queryparser.add_boolean_prefix("dogegory", "XDOG", false);
     queryparser.set_default_op(Xapian::Query::OP_NEAR);
     for (const test *p = test_near_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2867,7 +2867,7 @@
     queryparser.add_boolean_prefix("dogegory", "XDOG", false);
     queryparser.set_default_op(Xapian::Query::OP_PHRASE);
     for (const test *p = test_phrase_queries; p->query; ++p) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p->expect)
 	    expect = p->expect;
 	else
@@ -2937,7 +2937,7 @@
     const test *p = test_stopword_group_or_queries;
     for (int i = 1; i <= 2; ++i) {
 	for ( ; p->query; ++p) {
-	    string expect, parsed;
+	    std::string expect, parsed;
 	    if (p->expect)
 		expect = p->expect;
 	    else
@@ -3042,7 +3042,7 @@
     Xapian::QueryParser qp;
     const auto flags = qp.FLAG_DEFAULT | qp.FLAG_NO_POSITIONS;
     for (const test& p : tests) {
-	string expect, parsed;
+	std::string expect, parsed;
 	if (p.expect)
 	    expect = p.expect;
 	else
diff -ur xapian-core-1.4.21/tests/api_replacedoc.cc xapian-core-1.4.21/tests/api_replacedoc.cc
--- xapian-core-1.4.21/tests/api_replacedoc.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_replacedoc.cc	2022-11-08 16:44:15.484461486 +0100
@@ -118,7 +118,7 @@
 DEFINE_TESTCASE(modtermwdf1, writable) {
     Xapian::WritableDatabase db(get_writable_database());
 
-    string bdt(basic_docterms());
+    std::string bdt(basic_docterms());
 
     // Add a simple document.
     Xapian::Document doc1(basic_doc());
diff -ur xapian-core-1.4.21/tests/api_replicate.cc xapian-core-1.4.21/tests/api_replicate.cc
--- xapian-core-1.4.21/tests/api_replicate.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_replicate.cc	2022-11-08 16:44:15.552461245 +0100
@@ -53,18 +53,18 @@
 
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
 
-static void rmtmpdir(const string & path) {
+static void rmtmpdir(const std::string & path) {
     rm_rf(path);
 }
 
-static void mktmpdir(const string & path) {
+static void mktmpdir(const std::string & path) {
     rmtmpdir(path);
     if (mkdir(path.c_str(), 0700) == -1 && errno != EEXIST) {
 	FAIL_TEST("Can't make temporary directory");
     }
 }
 
-static off_t get_file_size(const string & path) {
+static off_t get_file_size(const std::string & path) {
     off_t size = file_size(path);
     if (errno) {
 	FAIL_TEST("Can't stat '" << path << "'");
@@ -104,7 +104,7 @@
 
 // Make a truncated copy of a file.
 static off_t
-truncated_copy(const string & srcpath, const string & destpath, off_t tocopy)
+truncated_copy(const std::string & srcpath, const std::string & destpath, off_t tocopy)
 {
     FD fdin(open(srcpath.c_str(), O_RDONLY | O_BINARY));
     if (fdin == -1) {
@@ -137,7 +137,7 @@
 }
 
 static void
-get_changeset(const string & changesetpath,
+get_changeset(const std::string & changesetpath,
 	      Xapian::DatabaseMaster & master,
 	      Xapian::DatabaseReplica & replica,
 	      int expected_changesets,
@@ -161,7 +161,7 @@
 }
 
 static int
-apply_changeset(const string & changesetpath,
+apply_changeset(const std::string & changesetpath,
 		Xapian::DatabaseReplica & replica,
 		int expected_changesets,
 		int expected_fullcopies,
@@ -201,13 +201,13 @@
 static int
 replicate(Xapian::DatabaseMaster & master,
 	  Xapian::DatabaseReplica & replica,
-	  const string & tempdir,
+	  const std::string & tempdir,
 	  int expected_changesets,
 	  int expected_fullcopies,
 	  bool expected_changed,
 	  bool full_copy = false)
 {
-    string changesetpath = tempdir + "/changeset";
+    std::string changesetpath = tempdir + "/changeset";
     get_changeset(changesetpath, master, replica,
 		  expected_changesets,
 		  expected_fullcopies,
@@ -221,7 +221,7 @@
 
 // Check that the databases held at the given path are identical.
 static void
-check_equal_dbs(const string & masterpath, const string & replicapath)
+check_equal_dbs(const std::string & masterpath, const std::string & replicapath)
 {
     Xapian::Database master(masterpath);
     Xapian::Database replica(replicapath);
@@ -256,9 +256,9 @@
 DEFINE_TESTCASE(replicate1, replicas) {
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(10);
 
@@ -269,7 +269,7 @@
 
     Xapian::WritableDatabase orig(get_named_writable_database("master"));
     Xapian::DatabaseMaster master(masterpath);
-    string replicapath = tempdir + "/replica";
+    std::string replicapath = tempdir + "/replica";
     {
 	Xapian::DatabaseReplica replica(replicapath);
 
@@ -337,20 +337,20 @@
     SKIP_TEST_FOR_BACKEND("glass"); // Glass doesn't currently support this.
     UNSET_MAX_CHANGESETS_AFTERWARDS;
 
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(10);
 
     {
 	Xapian::WritableDatabase orig(get_named_writable_database("master"));
 	Xapian::DatabaseMaster master(masterpath);
-	string replicapath = tempdir + "/replica";
+	std::string replicapath = tempdir + "/replica";
 	Xapian::DatabaseReplica replica(replicapath);
 
 	Xapian::DatabaseMaster master2(replicapath);
-	string replica2path = tempdir + "/replica2";
+	std::string replica2path = tempdir + "/replica2";
 	Xapian::DatabaseReplica replica2(replica2path);
 
 	// Add a document to the original database.
@@ -438,17 +438,17 @@
 static void
 replicate_with_brokenness(Xapian::DatabaseMaster & master,
 			  Xapian::DatabaseReplica & replica,
-			  const string & tempdir,
+			  const std::string & tempdir,
 			  int expected_changesets,
 			  int expected_fullcopies,
 			  bool expected_changed)
 {
-    string changesetpath = tempdir + "/changeset";
+    std::string changesetpath = tempdir + "/changeset";
     get_changeset(changesetpath, master, replica,
 		  1, 0, 1);
 
     // Try applying truncated changesets of various different lengths.
-    string brokenchangesetpath = tempdir + "/changeset_broken";
+    std::string brokenchangesetpath = tempdir + "/changeset_broken";
     off_t filesize = get_file_size(changesetpath);
     off_t len = 10;
     off_t copylen;
@@ -480,16 +480,16 @@
 DEFINE_TESTCASE(replicate3, replicas) {
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(10);
 
     {
 	Xapian::WritableDatabase orig(get_named_writable_database("master"));
 	Xapian::DatabaseMaster master(masterpath);
-	string replicapath = tempdir + "/replica";
+	std::string replicapath = tempdir + "/replica";
 	Xapian::DatabaseReplica replica(replicapath);
 
 	// Add a document to the original database.
@@ -531,16 +531,16 @@
 DEFINE_TESTCASE(replicate4, replicas) {
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(1);
 
     {
 	Xapian::WritableDatabase orig(get_named_writable_database("master"));
 	Xapian::DatabaseMaster master(masterpath);
-	string replicapath = tempdir + "/replica";
+	std::string replicapath = tempdir + "/replica";
 	Xapian::DatabaseReplica replica(replicapath);
 
 	// Add a document with no positions to the original database.
@@ -630,16 +630,16 @@
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     SKIP_TEST_FOR_BACKEND("chert");
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(2);
 
     {
 	Xapian::WritableDatabase orig(get_named_writable_database("master"));
 	Xapian::DatabaseMaster master(masterpath);
-	string replicapath = tempdir + "/replica";
+	std::string replicapath = tempdir + "/replica";
 	Xapian::DatabaseReplica replica(replicapath);
 
 	// Add a document with no positions to the original database.
@@ -761,16 +761,16 @@
 DEFINE_TESTCASE(replicate6, replicas) {
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(10);
 
     {
 	Xapian::WritableDatabase orig(get_named_writable_database("master"));
 	Xapian::DatabaseMaster master(masterpath);
-	string replicapath = tempdir + "/replica";
+	std::string replicapath = tempdir + "/replica";
 	Xapian::DatabaseReplica replica(replicapath);
 
 	// Add a document to the original database.
@@ -827,15 +827,15 @@
 DEFINE_TESTCASE(replicate7, replicas) {
 #ifdef XAPIAN_HAS_REMOTE_BACKEND
     UNSET_MAX_CHANGESETS_AFTERWARDS;
-    string tempdir = ".replicatmp";
+    std::string tempdir = ".replicatmp";
     mktmpdir(tempdir);
-    string masterpath = get_named_writable_database_path("master");
+    std::string masterpath = get_named_writable_database_path("master");
 
     set_max_changesets(10);
 
     Xapian::WritableDatabase orig(get_named_writable_database("master"));
     Xapian::DatabaseMaster master(masterpath);
-    string replicapath = tempdir + "/replica";
+    std::string replicapath = tempdir + "/replica";
     {
 	Xapian::DatabaseReplica replica(replicapath);
 
@@ -862,7 +862,7 @@
 
     {
 	// Corrupt replica by truncating all the files to size 0.
-	string d = replicapath;
+	std::string d = replicapath;
 	d += "/replica_1";
 	DIR * dir = opendir(d.c_str());
 	TEST(dir != NULL);
@@ -878,7 +878,7 @@
 	    // Skip '.' and '..'.
 	    if (entry->d_name[0] == '.') continue;
 
-	    string file = d;
+	    std::string file = d;
 	    file += '/';
 	    file += entry->d_name;
 	    int fd = open(file.c_str(), O_WRONLY|O_TRUNC, 0666);
diff -ur xapian-core-1.4.21/tests/api_serialise.cc xapian-core-1.4.21/tests/api_serialise.cc
--- xapian-core-1.4.21/tests/api_serialise.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_serialise.cc	2022-11-08 16:44:15.528461330 +0100
@@ -327,7 +327,7 @@
 
     ExceptionalPostingSource(failmode fail_) : fail(fail_) { }
 
-    string name() const {
+    std::string name() const {
 	return "ExceptionalPostingSource";
     }
 
@@ -385,7 +385,7 @@
 
     ExceptionalWeight(failmode fail_) : fail(fail_) { }
 
-    string name() const {
+    std::string name() const {
 	return "ExceptionalWeight";
     }
 
@@ -438,7 +438,7 @@
 
     ExceptionalMatchSpy(failmode fail_) : fail(fail_) { }
 
-    string name() const {
+    std::string name() const {
 	return "ExceptionalMatchSpy";
     }
 
diff -ur xapian-core-1.4.21/tests/api_snippets.cc xapian-core-1.4.21/tests/api_snippets.cc
--- xapian-core-1.4.21/tests/api_snippets.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_snippets.cc	2022-11-08 16:44:15.496461444 +0100
@@ -126,9 +126,9 @@
 
 /// Index file to a DB with TermGenerator.
 static void
-make_tg_db(Xapian::WritableDatabase &db, const string & source)
+make_tg_db(Xapian::WritableDatabase &db, const std::string & source)
 {
-    string file = test_driver::get_srcdir();
+    std::string file = test_driver::get_srcdir();
     file += "/testdata/";
     file += source;
     file += ".txt";
@@ -143,7 +143,7 @@
     while (!input.eof()) {
 	Xapian::Document doc;
 	tg.set_document(doc);
-	string line, data;
+	std::string line, data;
 	while (true) {
 	    getline(input, line);
 	    if (find_if(line.begin(), line.end(), C_isnotspace) == line.end())
@@ -273,14 +273,14 @@
     Xapian::MSet mset = enquire.get_mset(0, 0);
 
     // A non-matching text
-    const char *input = "A string without a match.";
+    const char *input = "A std::string without a match.";
     size_t len = strlen(input);
 
     // By default, snippet() returns len bytes of input without markup
     unsigned flags = 0;
     TEST_STRINGS_EQUAL(mset.snippet(input, len, stem, 0), input);
 
-    // force snippet() to return the empty string if no term got matched
+    // force snippet() to return the empty std::string if no term got matched
     flags |= Xapian::MSet::SNIPPET_EMPTY_WITHOUT_MATCH;
     TEST_STRINGS_EQUAL(mset.snippet(input, len, stem, flags), "");
 
@@ -510,7 +510,7 @@
     size_t len = strlen(input);
 
     unsigned flags = Xapian::MSet::SNIPPET_CJK_NGRAM;
-    string s;
+    std::string s;
     s = mset.snippet(input, len, stem, flags, "<b>", "</b>", "...");
     TEST_STRINGS_EQUAL(s, "明末時<b>已</b><b>經</b>有香港地方的概念");
 
diff -ur xapian-core-1.4.21/tests/api_sorting.cc xapian-core-1.4.21/tests/api_sorting.cc
--- xapian-core-1.4.21/tests/api_sorting.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_sorting.cc	2022-11-08 16:44:15.556461230 +0100
@@ -44,7 +44,7 @@
 
 	for (auto m = mset.begin(); m != mset.end(); ++m) {
 	    const string& data = m.get_document().get_data();
-	    string exp;
+	    std::string exp;
 	    exp += data[3];
 	    exp += string(2, '\0');
 	    exp += data[1];
@@ -63,7 +63,7 @@
 
 	for (auto m = mset.begin(); m != mset.end(); ++m) {
 	    const string& data = m.get_document().get_data();
-	    string exp;
+	    std::string exp;
 	    exp += data[3];
 	    exp += string(2, '\0');
 	    exp += char(0xff - data[1]);
@@ -84,7 +84,7 @@
 
 	for (auto m = mset.begin(); m != mset.end(); ++m) {
 	    const string& data = m.get_document().get_data();
-	    string exp;
+	    std::string exp;
 	    exp += string(2, '\0');
 	    exp += data[3];
 	    exp += string(2, '\0');
@@ -105,7 +105,7 @@
 
 	for (auto m = mset.begin(); m != mset.end(); ++m) {
 	    const string& data = m.get_document().get_data();
-	    string exp;
+	    std::string exp;
 	    if (data.size() > 10) exp += data[10];
 	    exp += string(2, '\0');
 	    exp += char(0xff - data[1]);
diff -ur xapian-core-1.4.21/tests/api_spelling.cc xapian-core-1.4.21/tests/api_spelling.cc
--- xapian-core-1.4.21/tests/api_spelling.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_spelling.cc	2022-11-08 16:44:15.548461259 +0100
@@ -259,7 +259,7 @@
     db.add_spelling(target);
     db.commit();
 
-    string s = db.get_spelling_suggestion("\xe4\xb8\x8d", 3);
+    std::string s = db.get_spelling_suggestion("\xe4\xb8\x8d", 3);
     TEST_EQUAL(s, target);
 }
 
diff -ur xapian-core-1.4.21/tests/api_stem.cc xapian-core-1.4.21/tests/api_stem.cc
--- xapian-core-1.4.21/tests/api_stem.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_stem.cc	2022-11-08 16:44:15.532461315 +0100
@@ -31,13 +31,13 @@
 using namespace std;
 
 class MyStemImpl : public Xapian::StemImplementation {
-    string operator()(const string & word) {
+    std::string operator()(const std::string & word) {
 	if (word == "vanish")
 	    return string();
 	return word.substr(0, 3);
     }
 
-    string get_description() const {
+    std::string get_description() const {
 	return "MyStem()";
     }
 };
@@ -100,7 +100,7 @@
 
 /// Test invalid language names with various characters in.
 DEFINE_TESTCASE(stemlangs2, !backend) {
-    string lang("xdummy");
+    std::string lang("xdummy");
     for (unsigned ch = 0; ch <= 255; ++ch) {
 	lang[0] = char(ch);
 	TEST_EXCEPTION(Xapian::InvalidArgumentError, Xapian::Stem stem(lang));
diff -ur xapian-core-1.4.21/tests/api_termgen.cc xapian-core-1.4.21/tests/api_termgen.cc
--- xapian-core-1.4.21/tests/api_termgen.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_termgen.cc	2022-11-08 16:44:15.500461429 +0100
@@ -38,7 +38,7 @@
 
 namespace {
 struct test {
-    // A string of options, separated by commas.
+    // A std::string of options, separated by commas.
     // Valid options are:
     //  - cont: don't clear the document, so add to the previous output
     //  - nopos: Don't store positions.
@@ -701,7 +701,7 @@
 static string
 format_doc_termlist(const Xapian::Document & doc)
 {
-    string output;
+    std::string output;
     Xapian::TermIterator it;
     for (it = doc.termlist_begin(); it != doc.termlist_end(); ++it) {
 	if (!output.empty()) output += ' ';
@@ -734,7 +734,7 @@
     Xapian::TermGenerator termgen;
     Xapian::Document doc;
     termgen.set_document(doc);
-    string prefix;
+    std::string prefix;
 
     for (const test *p = test_simple; p->text; ++p) {
 	int weight = 1;
@@ -757,7 +757,7 @@
 		    ++o;
 	    } else if (strncmp(o, "stem=", 5) == 0) {
 		o += 5;
-		string stemmer;
+		std::string stemmer;
 		while (*o != '\0' && *o != ',') {
 		    stemmer += *o;
 		    ++o;
@@ -818,7 +818,7 @@
 	    termgen.increase_termpos();
 	}
 
-	string expect, output;
+	std::string expect, output;
 	expect = p->expect;
 	try {
 	    if (nopos) {
diff -ur xapian-core-1.4.21/tests/apitest.cc xapian-core-1.4.21/tests/apitest.cc
--- xapian-core-1.4.21/tests/apitest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/apitest.cc	2022-11-08 16:44:15.484461486 +0100
@@ -45,15 +45,15 @@
 }
 
 Xapian::Database
-get_database(const string &dbname)
+get_database(const std::string &dbname)
 {
     return backendmanager->get_database(dbname);
 }
 
 Xapian::Database
-get_database(const string &dbname, const string &dbname2)
+get_database(const std::string &dbname, const std::string &dbname2)
 {
-    vector<string> dbnames;
+    std::vector<string> dbnames;
     dbnames.push_back(dbname);
     dbnames.push_back(dbname2);
     return backendmanager->get_database(dbnames);
@@ -69,7 +69,7 @@
 }
 
 string
-get_database_path(const string &dbname)
+get_database_path(const std::string &dbname)
 {
     return backendmanager->get_database_path(dbname);
 }
@@ -84,7 +84,7 @@
 }
 
 Xapian::WritableDatabase
-get_writable_database(const string &dbname)
+get_writable_database(const std::string &dbname)
 {
     return backendmanager->get_writable_database("dbw", dbname);
 }
@@ -108,9 +108,9 @@
 }
 
 Xapian::Database
-get_remote_database(const string &dbname, unsigned int timeout)
+get_remote_database(const std::string &dbname, unsigned int timeout)
 {
-    vector<string> dbnames;
+    std::vector<string> dbnames;
     dbnames.push_back(dbname);
     return backendmanager->get_remote_database(dbnames, timeout);
 }
diff -ur xapian-core-1.4.21/tests/apitest.h xapian-core-1.4.21/tests/apitest.h
--- xapian-core-1.4.21/tests/apitest.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/apitest.h	2022-11-08 16:44:01.064512748 +0100
@@ -60,14 +60,14 @@
 // Skip the test for any backend not of the specified type.
 //
 // More precisely, this skips the test for any backend for which the
-// get_dbtype() function does not return a string starting with backend_prefix.
+// get_dbtype() function does not return a std::string starting with backend_prefix.
 // This allows backends like "multi_chert" to be covered by specifying "multi".
 void skip_test_unless_backend(const std::string & backend_prefix);
 
 // Skip the test for any backend of the specified type.
 //
 // More precisely, this skips the test for any backend for which the
-// get_dbtype() function returns a string starting with backend_prefix.  This
+// get_dbtype() function returns a std::string starting with backend_prefix.  This
 // allows backends like "multi_chert" to be covered by specifying "multi".
 void skip_test_for_backend(const std::string & backend_prefix);
 
diff -ur xapian-core-1.4.21/tests/api_unicode.cc xapian-core-1.4.21/tests/api_unicode.cc
--- xapian-core-1.4.21/tests/api_unicode.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_unicode.cc	2022-11-08 16:44:15.488461473 +0100
@@ -390,7 +390,7 @@
 }
 
 DEFINE_TESTCASE(utf8convert1, !backend) {
-    string s;
+    std::string s;
     Xapian::Unicode::append_utf8(s, 'a');
     Xapian::Unicode::append_utf8(s, 128);
     Xapian::Unicode::append_utf8(s, 160);
diff -ur xapian-core-1.4.21/tests/api_valuestream.cc xapian-core-1.4.21/tests/api_valuestream.cc
--- xapian-core-1.4.21/tests/api_valuestream.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_valuestream.cc	2022-11-08 16:44:15.556461230 +0100
@@ -42,7 +42,7 @@
 	Xapian::ValueIterator it = db.valuestream_begin(slot);
 	while (it != db.valuestream_end(slot)) {
 	    TEST_EQUAL(it.get_valueno(), slot);
-	    string value = *it;
+	    std::string value = *it;
 	    Xapian::docid did = it.get_docid();
 
 	    Xapian::Document doc = db.get_document(did);
@@ -68,7 +68,7 @@
 	    if (it == db.valuestream_end(slot)) break;
 	    while (it.skip_to(did), it != db.valuestream_end(slot)) {
 		TEST_EQUAL(it.get_valueno(), slot);
-		string value = *it;
+		std::string value = *it;
 
 		// Check that the skipped documents had no values.
 		Xapian::docid actual_did = it.get_docid();
@@ -128,7 +128,7 @@
 		if (positioned) {
 		    if (it == db.valuestream_end(slot)) break;
 		    TEST_EQUAL(it.get_valueno(), slot);
-		    string value = *it;
+		    std::string value = *it;
 
 		    // Check that the skipped documents had no values.
 		    Xapian::docid actual_did = it.get_docid();
diff -ur xapian-core-1.4.21/tests/api_weight.cc xapian-core-1.4.21/tests/api_weight.cc
--- xapian-core-1.4.21/tests/api_weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_weight.cc	2022-11-08 16:44:15.496461444 +0100
@@ -738,14 +738,14 @@
 
 // Test for various cases of normalization string.
 DEFINE_TESTCASE(tfidfweight1, !backend) {
-    // InvalidArgumentError should be thrown if normalization string is invalid
+    // InvalidArgumentError should be thrown if normalization std::string is invalid
     TEST_EXCEPTION(Xapian::InvalidArgumentError,
 	Xapian::TfIdfWeight b("JOHN_LENNON"));
 
     TEST_EXCEPTION(Xapian::InvalidArgumentError,
 	Xapian::TfIdfWeight b("LOL"));
 
-    /* Normalization string should be set to "ntn" by constructor if none is
+    /* Normalization std::string should be set to "ntn" by constructor if none is
       given. */
     Xapian::TfIdfWeight weight2;
     TEST_EQUAL(weight2.serialise(), Xapian::TfIdfWeight("ntn").serialise());
@@ -939,13 +939,13 @@
 
     Xapian::Database db;
 
-    string term1;
+    std::string term1;
 
     // When testing OP_SYNONYM, term2 is also set.
     // When testing OP_WILDCARD, term2 == "*".
     // When testing a repeated term, term2 == "=" for the first occurrence and
     // "_" for subsequent occurrences.
-    mutable string term2;
+    mutable std::string term2;
 
     Xapian::termcount & sum;
     Xapian::termcount & sum_squares;
@@ -955,8 +955,8 @@
     mutable Xapian::termcount wdf_upper;
 
     CheckStatsWeight(const Xapian::Database & db_,
-		     const string & term1_,
-		     const string & term2_,
+		     const std::string & term1_,
+		     const std::string & term2_,
 		     Xapian::termcount & sum_,
 		     Xapian::termcount & sum_squares_)
 	: factor(-1.0), db(db_), term1(term1_), term2(term2_),
@@ -981,7 +981,7 @@
     }
 
     CheckStatsWeight(const Xapian::Database & db_,
-		     const string & term_,
+		     const std::string & term_,
 		     Xapian::termcount & sum_,
 		     Xapian::termcount & sum_squares_)
 	: CheckStatsWeight(db_, term_, string(), sum_, sum_squares_) { }
@@ -1097,7 +1097,7 @@
     Xapian::Enquire enquire(db);
     Xapian::TermIterator a;
     for (a = db.allterms_begin(); a != db.allterms_end(); ++a) {
-	const string & term = *a;
+	const std::string & term = *a;
 	enquire.set_query(Xapian::Query(term));
 	Xapian::termcount sum = 0;
 	Xapian::termcount sum_squares = 0;
@@ -1131,9 +1131,9 @@
     Xapian::Enquire enquire(db);
     Xapian::TermIterator a;
     for (a = db.allterms_begin(); a != db.allterms_end(); ++a) {
-	const string & term1 = *a;
+	const std::string & term1 = *a;
 	if (++a == db.allterms_end()) break;
-	const string & term2 = *a;
+	const std::string & term2 = *a;
 	Xapian::Query q(Xapian::Query::OP_SYNONYM,
 			Xapian::Query(term1), Xapian::Query(term2));
 	tout << q.get_description() << endl;
@@ -1277,7 +1277,7 @@
     Xapian::Enquire enquire(db);
     Xapian::TermIterator a;
     for (a = db.allterms_begin(); a != db.allterms_end(); ++a) {
-	const string & term = *a;
+	const std::string & term = *a;
 	enquire.set_query(Xapian::Query(term, 1, 1) |
 			  Xapian::Query(term, 1, 2));
 	Xapian::termcount sum = 0;
diff -ur xapian-core-1.4.21/tests/api_wrdb.cc xapian-core-1.4.21/tests/api_wrdb.cc
--- xapian-core-1.4.21/tests/api_wrdb.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/api_wrdb.cc	2022-11-08 16:44:15.480461501 +0100
@@ -277,7 +277,7 @@
     for (Xapian::doccount i = 0; i < 2100; ++i) {
 	Xapian::Document doc;
 	for (Xapian::termcount t = 0; t < 100; ++t) {
-	    string term("foo");
+	    std::string term("foo");
 	    term += char(t ^ 70 ^ i);
 	    doc.add_posting(term, t);
 	}
@@ -294,7 +294,7 @@
 
     for (Xapian::doccount i = 1; i <= 240; ++i) {
 	Xapian::Document doc;
-	string term(i, 'X');
+	std::string term(i, 'X');
 	doc.add_term(term);
 	db.add_document(doc);
     }
@@ -767,7 +767,7 @@
 
     for (Xapian::docid i = 1; i <= maxdoc; ++i) {
 	// TEST_EXCEPTION writes to tout each time if the test is run
-	// in verbose mode and some string stream implementations get
+	// in verbose mode and some std::string stream implementations get
 	// very inefficient with large strings, so clear tout on each pass of
 	// the loop to speed up the test since the older information isn't
 	// interesting anyway.
@@ -1201,7 +1201,7 @@
 
     for (int n = 1; n <= 20; ++n) {
 	Xapian::Document doc;
-	string uterm = "U" + str(n % 16);
+	std::string uterm = "U" + str(n % 16);
 	doc.add_term(uterm);
 	doc.add_term(str(n));
 	doc.add_term(str(n ^ 9));
@@ -1220,7 +1220,7 @@
 	15, 15, 15, 15
     };
     for (int n = 1; n <= 20; ++n) {
-	string uterm = "U" + str(n % 16);
+	std::string uterm = "U" + str(n % 16);
 	if (uterm == "U2") {
 	    db.delete_document(uterm);
 	} else {
@@ -1235,7 +1235,7 @@
 	TEST_EQUAL(db.get_doccount(), sizes[n - 1]);
     }
 
-    string uterm = "U571";
+    std::string uterm = "U571";
     Xapian::Document doc;
     doc.add_term(uterm);
     doc.set_data("pass3");
@@ -1522,8 +1522,8 @@
     // Glass has a single version file per revision, rather than multiple base
     // files, so it simply can't get into the situations we are testing
     // recovery from.
-    const string & dbtype = get_dbtype();
-    string path = ".";
+    const std::string & dbtype = get_dbtype();
+    std::string path = ".";
     path += dbtype;
     path += "/dbw";
     const char * base_ext = ".baseB";
@@ -1642,7 +1642,7 @@
     db.add_synonym("goodbye", "farewell");
 
     Xapian::TermIterator t;
-    string s;
+    std::string s;
 
     // Try these tests twice - once before committing and once after.
     for (int times = 1; times <= 2; ++times) {
@@ -1750,7 +1750,7 @@
 	tout.str(string());
 	tout << "Term length " << i << endl;
 	Xapian::Document doc;
-	string term(i, 'X');
+	std::string term(i, 'X');
 	doc.add_term(term);
 	try {
 	    db.add_document(doc);
@@ -1768,7 +1768,7 @@
 	tout.str(string());
 	tout << "Term length " << j << endl;
 	Xapian::Document doc;
-	string term(j, 'X');
+	std::string term(j, 'X');
 	doc.add_term(term);
 	db.add_document(doc);
     }
@@ -1791,7 +1791,7 @@
 	    // exception message - we've got this wrong in two different ways
 	    // in the past!
 	    tout << e.get_msg() << endl;
-	    string target = " is ";
+	    std::string target = " is ";
 	    target += str(limit);
 	    target += " bytes";
 	    TEST(e.get_msg().find(target) != string::npos);
@@ -1865,7 +1865,7 @@
 	db.add_document(doc);
 	db.commit();
 
-	string synonym(255, 'x');
+	std::string synonym(255, 'x');
 	char buf[] = " iamafish!!!!!!!!!!";
 	for (int i = 33; i < 120; ++i) {
 	    db.add_synonym(buf, synonym);
@@ -1912,7 +1912,7 @@
 
     db.commit();
 
-    const string & db_path = get_named_writable_database_path("cursordelbug1");
+    const std::string & db_path = get_named_writable_database_path("cursordelbug1");
     TEST_EQUAL(Xapian::Database::check(db_path), 0);
 }
 
@@ -1920,17 +1920,17 @@
  *
  * Check that the values stored in the database match */
 static void
-check_vals(const Xapian::Database & db, const map<Xapian::docid, string> & vals)
+check_vals(const Xapian::Database & db, const std::map<Xapian::docid, string> & vals)
 {
     TEST_EQUAL(db.get_doccount(), vals.size());
     if (vals.empty()) return;
     TEST_REL(vals.rbegin()->first,<=,db.get_lastdocid());
-    map<Xapian::docid, string>::const_iterator i;
+    std::map<Xapian::docid, string>::const_iterator i;
     for (i = vals.begin(); i != vals.end(); ++i) {
 	tout.str(string());
 	tout << "Checking value in doc " << i->first << " - should be '" << i->second << "'\n";
 	Xapian::Document doc = db.get_document(i->first);
-	string dbval = doc.get_value(1);
+	std::string dbval = doc.get_value(1);
 	TEST_EQUAL(dbval, i->second);
 	if (dbval.empty()) {
 	    TEST_EQUAL(0, doc.values_count());
@@ -1957,12 +1957,12 @@
     const Xapian::doccount doccount = 1000;
     static_assert(doccount % 13 != 0, "doccount divisible by 13");
 
-    map<Xapian::docid, string> vals;
+    std::map<Xapian::docid, string> vals;
 
     for (Xapian::doccount num = 1; num <= doccount; ++num) {
 	tout.str(string());
 	Xapian::Document doc;
-	string val = "val" + str(num);
+	std::string val = "val" + str(num);
 	tout << "Setting val '" << val << "' in doc " << num << "\n";
 	doc.add_value(1, val);
 	db.add_document(doc);
@@ -1976,7 +1976,7 @@
     // the initial implementation of streaming values).
     {
 	Xapian::Document doc;
-	string val = "newval0";
+	std::string val = "newval0";
 	tout << "Setting val '" << val << "' in doc 2\n";
 	doc.add_value(1, val);
 	db.replace_document(2, doc);
@@ -2018,7 +2018,7 @@
 	tout.str(string());
 	Xapian::docid did = ((rand() >> 8) % doccount) + 1;
 	Xapian::Document doc;
-	string val;
+	std::string val;
 
 	if (num % 5 != 0) {
 	    val = "newval" + str(num);
diff -ur xapian-core-1.4.21/tests/dbcheck.cc xapian-core-1.4.21/tests/dbcheck.cc
--- xapian-core-1.4.21/tests/dbcheck.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/dbcheck.cc	2022-11-08 16:44:15.528461330 +0100
@@ -34,7 +34,7 @@
 		    const Xapian::PositionIterator & end,
 		    Xapian::termcount * count)
 {
-    string result;
+    std::string result;
     bool need_comma = false;
     Xapian::termcount c = 0;
     while (it != end) {
@@ -52,9 +52,9 @@
 }
 
 string
-postlist_to_string(const Xapian::Database & db, const string & tname)
+postlist_to_string(const Xapian::Database & db, const std::string & tname)
 {
-    string result;
+    std::string result;
     bool need_comma = false;
 
     for (Xapian::PostingIterator p = db.postlist_begin(tname);
@@ -64,7 +64,7 @@
 	    result += ", ";
 
 	Xapian::PositionIterator it(p.positionlist_begin());
-	string posrepr = positions_to_string(it, p.positionlist_end());
+	std::string posrepr = positions_to_string(it, p.positionlist_end());
 	if (!posrepr.empty()) {
 	    posrepr = ", pos=[" + posrepr + "]";
 	}
@@ -81,14 +81,14 @@
 string
 docterms_to_string(const Xapian::Database & db, Xapian::docid did)
 {
-    string result;
+    std::string result;
     bool need_comma = false;
 
     for (Xapian::TermIterator t = db.termlist_begin(did);
 	 t != db.termlist_end(did);
 	 ++t) {
 	Xapian::PositionIterator it(t.positionlist_begin());
-	string posrepr = positions_to_string(it, t.positionlist_end());
+	std::string posrepr = positions_to_string(it, t.positionlist_end());
 	if (!posrepr.empty()) {
 	    posrepr = ", pos=[" + posrepr + "]";
 	}
@@ -104,7 +104,7 @@
 string
 docstats_to_string(const Xapian::Database & db, Xapian::docid did)
 {
-    string result;
+    std::string result;
 
     result += "len=" + str(db.get_doclength(did));
 
@@ -112,9 +112,9 @@
 }
 
 string
-termstats_to_string(const Xapian::Database & db, const string & term)
+termstats_to_string(const Xapian::Database & db, const std::string & term)
 {
-    string result;
+    std::string result;
 
     result += "tf=" + str(db.get_termfreq(term));
     result += ",cf=" + str(db.get_collection_freq(term));
@@ -137,8 +137,8 @@
     // A map from term to a representation of the posting list for that term.
     // We build this up from the documents, and then check it against the
     // equivalent built up from the posting lists.
-    map<string, string> posting_reprs;
-    map<Xapian::valueno, string> value_reprs;
+    std::map<string, string> posting_reprs;
+    std::map<Xapian::valueno, string> value_reprs;
 
     Xapian::termcount doclen_lower_bound = Xapian::termcount(-1);
     Xapian::termcount doclen_upper_bound = 0;
@@ -179,9 +179,9 @@
 	    // Check the position lists are equal.
 	    Xapian::termcount tc1, tc2;
 	    Xapian::PositionIterator it1(t.positionlist_begin());
-	    string posrepr = positions_to_string(it1, t.positionlist_end(), &tc1);
+	    std::string posrepr = positions_to_string(it1, t.positionlist_end(), &tc1);
 	    Xapian::PositionIterator it2(t2.positionlist_begin());
-	    string posrepr2 = positions_to_string(it2, t2.positionlist_end(), &tc2);
+	    std::string posrepr2 = positions_to_string(it2, t2.positionlist_end(), &tc2);
 	    TEST_EQUAL(posrepr, posrepr2);
 	    TEST_EQUAL(tc1, tc2);
 	    try {
@@ -194,12 +194,12 @@
 	    if (!posrepr.empty()) {
 		posrepr = ",[" + posrepr + "]";
 	    }
-	    string posting_repr = "(" + str(did) + "," +
+	    std::string posting_repr = "(" + str(did) + "," +
 		    str(t.get_wdf()) + "/" + str(doclen) +
 		    posrepr + ")";
 
 	    // Append the representation to the list for the term.
-	    map<string, string>::iterator i = posting_reprs.find(*t);
+	    std::map<string, string>::iterator i = posting_reprs.find(*t);
 	    if (i == posting_reprs.end()) {
 		posting_reprs[*t] = posting_repr;
 	    } else {
@@ -212,10 +212,10 @@
 	     v != doc.values_end();
 	     ++v, ++vcount) {
 	    TEST((*v).size() != 0);
-	    string value_repr = "(" + str(did) + "," + *v + ")";
+	    std::string value_repr = "(" + str(did) + "," + *v + ")";
 
 	    // Append the values to the value lists.
-	    map<Xapian::valueno, string>::iterator i;
+	    std::map<Xapian::valueno, string>::iterator i;
 	    i = value_reprs.find(v.get_valueno());
 	    if (i == value_reprs.end()) {
 		value_reprs[v.get_valueno()] = value_repr;
@@ -241,7 +241,7 @@
     TEST_REL(doclen_upper_bound, <=, db.get_doclength_upper_bound());
 
     Xapian::TermIterator t;
-    map<string, string>::const_iterator i;
+    std::map<string, string>::const_iterator i;
     for (t = db.allterms_begin(), i = posting_reprs.begin();
 	 t != db.allterms_end();
 	 ++t, ++i) {
@@ -252,7 +252,7 @@
 	Xapian::doccount tf_count = 0;
 	Xapian::termcount cf_count = 0;
 	Xapian::termcount wdf_upper_bound = 0;
-	string posting_repr;
+	std::string posting_repr;
 	bool need_comma = false;
 	for (Xapian::PostingIterator p = db.postlist_begin(*t);
 	     p != db.postlist_end(*t);
@@ -265,7 +265,7 @@
 	    cf_count += p.get_wdf();
 
 	    Xapian::PositionIterator it(p.positionlist_begin());
-	    string posrepr = positions_to_string(it, p.positionlist_end());
+	    std::string posrepr = positions_to_string(it, p.positionlist_end());
 	    if (!posrepr.empty()) {
 		posrepr = ",[" + posrepr + "]";
 	    }
@@ -285,11 +285,11 @@
     }
     TEST(i == posting_reprs.end());
 
-    map<Xapian::valueno, string>::const_iterator j;
+    std::map<Xapian::valueno, string>::const_iterator j;
     for (j = value_reprs.begin(); j != value_reprs.end(); ++j) {
-	string value_repr;
-	string value_lower_bound;
-	string value_upper_bound;
+	std::string value_repr;
+	std::string value_lower_bound;
+	std::string value_upper_bound;
 	bool first = true;
 	for (Xapian::ValueIterator v = db.valuestream_begin(j->first);
 	     v != db.valuestream_end(j->first); ++v) {
diff -ur xapian-core-1.4.21/tests/harness/backendmanager.cc xapian-core-1.4.21/tests/harness/backendmanager.cc
--- xapian-core-1.4.21/tests/harness/backendmanager.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager.cc	2022-11-08 16:44:15.524461344 +0100
@@ -47,7 +47,7 @@
 
 void
 BackendManager::index_files_to_database(Xapian::WritableDatabase & database,
-					const vector<string> & files)
+					const std::vector<string> & files)
 {
     FileIndexer(datadir, files).index_to(database);
 }
@@ -57,7 +57,7 @@
  *  an exception if there was an error (eg not a directory).
  */
 bool
-BackendManager::create_dir_if_needed(const string &dirname)
+BackendManager::create_dir_if_needed(const std::string &dirname)
 {
     if (mkdir(dirname.c_str(), 0700) == 0) {
 	return true;
@@ -84,25 +84,25 @@
 }
 
 string
-BackendManager::do_get_database_path(const vector<string> &)
+BackendManager::do_get_database_path(const std::vector<string> &)
 {
     throw Xapian::InvalidArgumentError("Path isn't meaningful for this database type");
 }
 
 Xapian::Database
-BackendManager::do_get_database(const vector<string> & files)
+BackendManager::do_get_database(const std::vector<string> & files)
 {
     return Xapian::Database(do_get_database_path(files));
 }
 
 Xapian::Database
-BackendManager::get_database(const vector<string> & files)
+BackendManager::get_database(const std::vector<string> & files)
 {
     return do_get_database(files);
 }
 
 Xapian::Database
-BackendManager::get_database(const string & file)
+BackendManager::get_database(const std::string & file)
 {
     return do_get_database(vector<string>(1, file));
 }
@@ -113,7 +113,7 @@
 					 const std::string &),
 			     const std::string &arg)
 {
-    string dbleaf = "db__";
+    std::string dbleaf = "db__";
     dbleaf += dbname;
     const string& path = get_generated_database_path(dbleaf);
     if (path.empty()) {
@@ -132,9 +132,9 @@
     }
     rm_rf(path);
 
-    string tmp_dbleaf(dbleaf);
+    std::string tmp_dbleaf(dbleaf);
     tmp_dbleaf += '~';
-    string tmp_path(path);
+    std::string tmp_path(path);
     tmp_path += '~';
 
     {
@@ -155,7 +155,7 @@
 					      const std::string &),
 				  const std::string &arg)
 {
-    string dbleaf = "db__";
+    std::string dbleaf = "db__";
     dbleaf += dbname;
     const string& path = get_generated_database_path(dbleaf);
     if (path_exists(path)) {
@@ -167,9 +167,9 @@
     }
     rm_rf(path);
 
-    string tmp_dbleaf(dbleaf);
+    std::string tmp_dbleaf(dbleaf);
     tmp_dbleaf += '~';
-    string tmp_path(path);
+    std::string tmp_path(path);
     tmp_path += '~';
 
     {
@@ -189,19 +189,19 @@
 }
 
 string
-BackendManager::get_database_path(const vector<string> & files)
+BackendManager::get_database_path(const std::vector<string> & files)
 {
     return do_get_database_path(files);
 }
 
 string
-BackendManager::get_database_path(const string & file)
+BackendManager::get_database_path(const std::string & file)
 {
     return do_get_database_path(vector<string>(1, file));
 }
 
 Xapian::WritableDatabase
-BackendManager::get_writable_database(const string &, const string &)
+BackendManager::get_writable_database(const std::string &, const std::string &)
 {
     throw Xapian::InvalidArgumentError("Attempted to open a disabled database");
 }
@@ -209,7 +209,7 @@
 Xapian::WritableDatabase
 BackendManager::get_remote_writable_database(string)
 {
-    string msg = "BackendManager::get_remote_writable_database() "
+    std::string msg = "BackendManager::get_remote_writable_database() "
 		 "called for non-remote database (type is ";
     msg += get_dbtype();
     msg += ')';
@@ -245,9 +245,9 @@
 { }
 
 Xapian::Database
-BackendManager::get_remote_database(const vector<string> &, unsigned int)
+BackendManager::get_remote_database(const std::vector<string> &, unsigned int)
 {
-    string msg = "BackendManager::get_remote_database() called for non-remote database (type is ";
+    std::string msg = "BackendManager::get_remote_database() called for non-remote database (type is ";
     msg += get_dbtype();
     msg += ')';
     throw Xapian::InvalidOperationError(msg);
@@ -257,7 +257,7 @@
 BackendManager::get_writable_database_args(const std::string&,
 					   unsigned int)
 {
-    string msg = "BackendManager::get_writable_database_args() "
+    std::string msg = "BackendManager::get_writable_database_args() "
 		 "called for non-remote database (type is ";
     msg += get_dbtype();
     msg += ')';
@@ -273,7 +273,7 @@
 Xapian::WritableDatabase
 BackendManager::get_writable_database_again()
 {
-    string msg = "Backend ";
+    std::string msg = "Backend ";
     msg += get_dbtype();
     msg += " doesn't support get_writable_database_again()";
     throw Xapian::InvalidOperationError(msg);
@@ -282,7 +282,7 @@
 string
 BackendManager::get_writable_database_path_again()
 {
-    string msg = "Backend ";
+    std::string msg = "Backend ";
     msg += get_dbtype();
     msg += " doesn't support get_writable_database_path_again()";
     throw Xapian::InvalidOperationError(msg);
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_chert.cc xapian-core-1.4.21/tests/harness/backendmanager_chert.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_chert.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_chert.cc	2022-11-08 16:44:15.516461372 +0100
@@ -46,9 +46,9 @@
 }
 
 string
-BackendManagerChert::do_get_database_path(const vector<string> & files)
+BackendManagerChert::do_get_database_path(const std::vector<string> & files)
 {
-    string db_path = CACHE_DIRECTORY "/db";
+    std::string db_path = CACHE_DIRECTORY "/db";
     for (const string& file : files) {
 	db_path += "__";
 	db_path += file;
@@ -57,7 +57,7 @@
     if (!dir_exists(db_path)) {
 	// No cached DB exists.  Create at a temporary path and rename
 	// so we don't leave a partial DB in place upon failure.
-	string tmp_path = db_path + ".tmp";
+	std::string tmp_path = db_path + ".tmp";
 	// Make sure there's nothing existing at our temporary path.
 	rm_rf(tmp_path);
 	auto flags = Xapian::DB_CREATE|Xapian::DB_BACKEND_CHERT;
@@ -73,11 +73,11 @@
 }
 
 Xapian::WritableDatabase
-BackendManagerChert::get_writable_database(const string & name,
-					   const string & file)
+BackendManagerChert::get_writable_database(const std::string & name,
+					   const std::string & file)
 {
     last_wdb_name = name;
-    string db_path = CACHE_DIRECTORY "/" + name;
+    std::string db_path = CACHE_DIRECTORY "/" + name;
 
     // We can't use a cached version, as it may have been modified by the
     // testcase.
@@ -85,13 +85,13 @@
 
     auto flags = Xapian::DB_CREATE|Xapian::DB_BACKEND_CHERT;
     Xapian::WritableDatabase wdb(db_path, flags, BLOCK_SIZE);
-    index_files_to_database(wdb, vector<string>(1, file));
+    index_files_to_database(wdb, std::vector<string>(1, file));
 
     return wdb;
 }
 
 string
-BackendManagerChert::get_writable_database_path(const string & name)
+BackendManagerChert::get_writable_database_path(const std::string & name)
 {
     return CACHE_DIRECTORY "/" + name;
 }
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_chert.h xapian-core-1.4.21/tests/harness/backendmanager_chert.h
--- xapian-core-1.4.21/tests/harness/backendmanager_chert.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_chert.h	2022-11-08 16:44:01.040512833 +0100
@@ -45,7 +45,7 @@
   public:
     BackendManagerChert(const std::string& datadir_);
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a Chert Xapian::WritableDatabase object indexing a single file.
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_glass.cc xapian-core-1.4.21/tests/harness/backendmanager_glass.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_glass.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_glass.cc	2022-11-08 16:44:15.512461387 +0100
@@ -46,9 +46,9 @@
 }
 
 string
-BackendManagerGlass::do_get_database_path(const vector<string> & files)
+BackendManagerGlass::do_get_database_path(const std::vector<string> & files)
 {
-    string db_path = CACHE_DIRECTORY "/db";
+    std::string db_path = CACHE_DIRECTORY "/db";
     for (const string& file : files) {
 	db_path += "__";
 	db_path += file;
@@ -57,7 +57,7 @@
     if (!dir_exists(db_path)) {
 	// No cached DB exists.  Create at a temporary path and rename
 	// so we don't leave a partial DB in place upon failure.
-	string tmp_path = db_path + ".tmp";
+	std::string tmp_path = db_path + ".tmp";
 	// Make sure there's nothing existing at our temporary path.
 	rm_rf(tmp_path);
 	auto flags = Xapian::DB_CREATE|Xapian::DB_BACKEND_GLASS;
@@ -73,11 +73,11 @@
 }
 
 Xapian::WritableDatabase
-BackendManagerGlass::get_writable_database(const string & name,
-					   const string & file)
+BackendManagerGlass::get_writable_database(const std::string & name,
+					   const std::string & file)
 {
     last_wdb_name = name;
-    string db_path = CACHE_DIRECTORY "/" + name;
+    std::string db_path = CACHE_DIRECTORY "/" + name;
 
     // We can't use a cached version, as it may have been modified by the
     // testcase.
@@ -85,13 +85,13 @@
 
     auto flags = Xapian::DB_CREATE|Xapian::DB_BACKEND_GLASS;
     Xapian::WritableDatabase wdb(db_path, flags, BLOCK_SIZE);
-    index_files_to_database(wdb, vector<string>(1, file));
+    index_files_to_database(wdb, std::vector<string>(1, file));
 
     return wdb;
 }
 
 string
-BackendManagerGlass::get_writable_database_path(const string & name)
+BackendManagerGlass::get_writable_database_path(const std::string & name)
 {
     return CACHE_DIRECTORY "/" + name;
 }
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_glass.h xapian-core-1.4.21/tests/harness/backendmanager_glass.h
--- xapian-core-1.4.21/tests/harness/backendmanager_glass.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_glass.h	2022-11-08 16:44:01.048512805 +0100
@@ -45,7 +45,7 @@
   public:
     BackendManagerGlass(const std::string& datadir_);
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a Glass Xapian::WritableDatabase object indexing a single file.
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_inmemory.cc xapian-core-1.4.21/tests/harness/backendmanager_inmemory.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_inmemory.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_inmemory.cc	2022-11-08 16:44:15.520461359 +0100
@@ -31,7 +31,7 @@
 }
 
 Xapian::Database
-BackendManagerInMemory::do_get_database(const vector<string>& files)
+BackendManagerInMemory::do_get_database(const std::vector<string>& files)
 {
     Xapian::WritableDatabase wdb(string(), Xapian::DB_BACKEND_INMEMORY);
     index_files_to_database(wdb, files);
@@ -43,7 +43,7 @@
 					      const string& file)
 {
     Xapian::WritableDatabase wdb(string(), Xapian::DB_BACKEND_INMEMORY);
-    index_files_to_database(wdb, vector<string>(1, file));
+    index_files_to_database(wdb, std::vector<string>(1, file));
     return wdb;
 }
 
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_inmemory.h xapian-core-1.4.21/tests/harness/backendmanager_inmemory.h
--- xapian-core-1.4.21/tests/harness/backendmanager_inmemory.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_inmemory.h	2022-11-08 16:44:01.040512833 +0100
@@ -45,7 +45,7 @@
     BackendManagerInMemory(const std::string& datadir_)
 	: BackendManager(datadir_) {}
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a InMemory Xapian::WritableDatabase object indexing a single file.
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_multi.cc xapian-core-1.4.21/tests/harness/backendmanager_multi.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_multi.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_multi.cc	2022-11-08 16:44:15.520461359 +0100
@@ -37,7 +37,7 @@
 using namespace std;
 
 BackendManagerMulti::BackendManagerMulti(const std::string& datadir_,
-					 vector<BackendManager*> sub_managers_)
+					 std::vector<BackendManager*> sub_managers_)
     : BackendManager(datadir_),
       sub_managers(sub_managers_)
 {
@@ -57,7 +57,7 @@
 std::string
 BackendManagerMulti::get_dbtype() const
 {
-    string dbtype = "multi";
+    std::string dbtype = "multi";
     if (sub_managers.size() == 2 &&
 	sub_managers[0]->get_dbtype() == sub_managers[1]->get_dbtype()) {
 	dbtype += "_" + sub_managers[0]->get_dbtype();
@@ -73,9 +73,9 @@
 
 string
 BackendManagerMulti::createdb_multi(const string& name,
-				    const vector<string>& files)
+				    const std::vector<string>& files)
 {
-    string dbname;
+    std::string dbname;
     if (!name.empty()) {
 	dbname = name;
     } else {
@@ -86,13 +86,13 @@
 	}
     }
 
-    string db_path = cachedir;
+    std::string db_path = cachedir;
     db_path += '/';
     db_path += dbname;
 
     if (!name.empty()) {
 	if (unlink(db_path.c_str()) < 0 && errno != ENOENT) {
-	    string msg = "Couldn't unlink file '";
+	    std::string msg = "Couldn't unlink file '";
 	    msg += db_path;
 	    msg += "' (";
 	    errno_to_string(errno, msg);
@@ -103,10 +103,10 @@
 	if (file_exists(db_path)) return db_path;
     }
 
-    string tmpfile = db_path + ".tmp";
+    std::string tmpfile = db_path + ".tmp";
     ofstream out(tmpfile.c_str());
     if (!out.is_open()) {
-	string msg = "Couldn't create file '";
+	std::string msg = "Couldn't create file '";
 	msg += tmpfile;
 	msg += "' (";
 	errno_to_string(errno, msg);
@@ -118,7 +118,7 @@
     // a multi-db combining them contains the documents in the expected order.
     Xapian::WritableDatabase dbs;
 
-    string dbbase = db_path;
+    std::string dbbase = db_path;
     dbbase += "___";
     size_t dbbase_len = dbbase.size();
 
@@ -140,7 +140,7 @@
 	    dbbase += str(n);
 	    Xapian::WritableDatabase remote_db(dbbase, flags);
 	    remote_db.close();
-	    string args = sub_managers[n]->get_writable_database_args(dbbase,
+	    std::string args = sub_managers[n]->get_writable_database_args(dbbase,
 								      300000);
 
 	    dbs.add_database(
@@ -149,7 +149,7 @@
 	    out << "remote :" << BackendManager::get_xapian_progsrv_command()
 		<< " " << args << '\n';
 	} else {
-	    string msg = "Unknown multidb subtype: ";
+	    std::string msg = "Unknown multidb subtype: ";
 	    msg += subtype;
 	    throw msg;
 	}
@@ -183,7 +183,7 @@
 }
 
 string
-BackendManagerMulti::do_get_database_path(const vector<string> & files)
+BackendManagerMulti::do_get_database_path(const std::vector<string> & files)
 {
     return createdb_multi(string(), files);
 }
@@ -191,7 +191,7 @@
 Xapian::WritableDatabase
 BackendManagerMulti::get_writable_database(const string& name, const string& file)
 {
-    vector<string> files;
+    std::vector<string> files;
     if (!file.empty()) files.push_back(file);
     return Xapian::WritableDatabase(createdb_multi(name, files));
 }
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_multi.h xapian-core-1.4.21/tests/harness/backendmanager_multi.h
--- xapian-core-1.4.21/tests/harness/backendmanager_multi.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_multi.h	2022-11-08 16:44:01.044512820 +0100
@@ -56,7 +56,7 @@
     BackendManagerMulti(const std::string& datadir_,
 			std::vector<BackendManager*> sub_manager_);
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     Xapian::Database get_remote_database(const std::vector<std::string>& files,
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.cc xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.cc	2022-11-08 16:44:15.520461359 +0100
@@ -38,7 +38,7 @@
 }
 
 Xapian::Database
-BackendManagerRemoteProg::do_get_database(const vector<string> & files)
+BackendManagerRemoteProg::do_get_database(const std::vector<string> & files)
 {
     // Default to a long (5 minute) timeout so that tests won't fail just
     // because the host is slow or busy.
@@ -46,10 +46,10 @@
 }
 
 Xapian::WritableDatabase
-BackendManagerRemoteProg::get_writable_database(const string & name,
-						const string & file)
+BackendManagerRemoteProg::get_writable_database(const std::string & name,
+						const std::string & file)
 {
-    string args = get_writable_database_args(name, file);
+    std::string args = get_writable_database_args(name, file);
 
 #ifdef HAVE_VALGRIND
     if (RUNNING_ON_VALGRIND) {
@@ -73,10 +73,10 @@
 }
 
 Xapian::Database
-BackendManagerRemoteProg::get_remote_database(const vector<string> & files,
+BackendManagerRemoteProg::get_remote_database(const std::vector<string> & files,
 					      unsigned int timeout)
 {
-    string args = get_remote_database_args(files, timeout);
+    std::string args = get_remote_database_args(files, timeout);
 
 #ifdef HAVE_VALGRIND
     if (RUNNING_ON_VALGRIND) {
@@ -90,7 +90,7 @@
 Xapian::Database
 BackendManagerRemoteProg::get_database_by_path(const string& path)
 {
-    string args = get_remote_database_args(path, 300000);
+    std::string args = get_remote_database_args(path, 300000);
 
 #ifdef HAVE_VALGRIND
     if (RUNNING_ON_VALGRIND) {
@@ -104,7 +104,7 @@
 Xapian::Database
 BackendManagerRemoteProg::get_writable_database_as_database()
 {
-    string args = get_writable_database_as_database_args();
+    std::string args = get_writable_database_as_database_args();
 
 #ifdef HAVE_VALGRIND
     if (RUNNING_ON_VALGRIND) {
@@ -118,7 +118,7 @@
 Xapian::WritableDatabase
 BackendManagerRemoteProg::get_writable_database_again()
 {
-    string args = get_writable_database_again_args();
+    std::string args = get_writable_database_again_args();
 
 #ifdef HAVE_VALGRIND
     if (RUNNING_ON_VALGRIND) {
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.h xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.h
--- xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_remoteprog.h	2022-11-08 16:44:01.036512848 +0100
@@ -48,7 +48,7 @@
     explicit BackendManagerRemoteProg(BackendManager* sub_manager_)
 	: BackendManagerRemote(sub_manager_) { }
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a RemoteProg Xapian::WritableDatabase object indexing a single file.
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.cc xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.cc	2022-11-08 16:44:15.516461372 +0100
@@ -105,7 +105,7 @@
 }
 
 static int
-launch_xapian_tcpsrv(const string & args)
+launch_xapian_tcpsrv(const std::string & args)
 {
     int port = DEFAULT_PORT;
 
@@ -113,7 +113,7 @@
     // if xapian-tcpsrv doesn't start listening successfully.
     signal(SIGCHLD, SIG_DFL);
 try_next_port:
-    string cmd = XAPIAN_TCPSRV " --one-shot --interface " LOCALHOST " --port ";
+    std::string cmd = XAPIAN_TCPSRV " --one-shot --interface " LOCALHOST " --port ";
     cmd += str(port);
     cmd += " ";
     cmd += args;
@@ -122,7 +122,7 @@
 #endif
     int fds[2];
     if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, PF_UNSPEC, fds) < 0) {
-	string msg("Couldn't create socketpair: ");
+	std::string msg("Couldn't create socketpair: ");
 	errno_to_string(errno, msg);
 	throw msg;
     }
@@ -154,7 +154,7 @@
 	// Couldn't fork.
 	int fork_errno = errno;
 	close(fds[0]);
-	string msg("Couldn't fork: ");
+	std::string msg("Couldn't fork: ");
 	errno_to_string(fork_errno, msg);
 	throw msg;
     }
@@ -164,14 +164,14 @@
     // Wrap the file descriptor in a FILE * so we can read lines using fgets().
     FILE * fh = fdopen(fds[0], "r");
     if (fh == NULL) {
-	string msg("Failed to run command '");
+	std::string msg("Failed to run command '");
 	msg += cmd;
 	msg += "': ";
 	errno_to_string(errno, msg);
 	throw msg;
     }
 
-    string output;
+    std::string output;
     while (true) {
 	char buf[256];
 	if (fgets(buf, sizeof(buf), fh) == NULL) {
@@ -179,7 +179,7 @@
 	    // Wait for the child to exit.
 	    int status;
 	    if (waitpid(child, &status, 0) == -1) {
-		string msg("waitpid failed: ");
+		std::string msg("waitpid failed: ");
 		errno_to_string(errno, msg);
 		throw msg;
 	    }
@@ -191,7 +191,7 @@
 		    goto try_next_port;
 		}
 	    }
-	    string msg("Failed to get 'Listening...' from command '");
+	    std::string msg("Failed to get 'Listening...' from command '");
 	    msg += cmd;
 	    msg += "' (output: ";
 	    msg += output;
@@ -238,7 +238,7 @@
 XAPIAN_NORETURN(static void win32_throw_error_string(const char * str));
 static void win32_throw_error_string(const char * str)
 {
-    string msg(str);
+    std::string msg(str);
     char * error = 0;
     DWORD len;
     len = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_ALLOCATE_BUFFER,
@@ -259,12 +259,12 @@
 // This implementation uses the WIN32 API to start xapian-tcpsrv as a child
 // process and read its output using a pipe.
 static int
-launch_xapian_tcpsrv(const string & args)
+launch_xapian_tcpsrv(const std::string & args)
 {
     int port = DEFAULT_PORT;
 
 try_next_port:
-    string cmd = XAPIAN_TCPSRV " --one-shot --interface " LOCALHOST " --port ";
+    std::string cmd = XAPIAN_TCPSRV " --one-shot --interface " LOCALHOST " --port ";
     cmd += str(port);
     cmd += " ";
     cmd += args;
@@ -300,7 +300,7 @@
     CloseHandle(hWrite);
     CloseHandle(procinfo.hThread);
 
-    string output;
+    std::string output;
     FILE *fh = fdopen(_open_osfhandle(intptr_t(hRead), O_RDONLY), "r");
     while (true) {
 	char buf[256];
@@ -319,7 +319,7 @@
 		// in use.
 		goto try_next_port;
 	    }
-	    string msg("Failed to get 'Listening...' from command '");
+	    std::string msg("Failed to get 'Listening...' from command '");
 	    msg += cmd;
 	    msg += "' (output: ";
 	    msg += output;
@@ -353,7 +353,7 @@
 }
 
 Xapian::Database
-BackendManagerRemoteTcp::do_get_database(const vector<string> & files)
+BackendManagerRemoteTcp::do_get_database(const std::vector<string> & files)
 {
     // Default to a long (5 minute) timeout so that tests won't fail just
     // because the host is slow or busy.
@@ -361,19 +361,19 @@
 }
 
 Xapian::WritableDatabase
-BackendManagerRemoteTcp::get_writable_database(const string & name,
-					       const string & file)
+BackendManagerRemoteTcp::get_writable_database(const std::string & name,
+					       const std::string & file)
 {
-    string args = get_writable_database_args(name, file);
+    std::string args = get_writable_database_args(name, file);
     int port = launch_xapian_tcpsrv(args);
     return Xapian::Remote::open_writable(LOCALHOST, port);
 }
 
 Xapian::Database
-BackendManagerRemoteTcp::get_remote_database(const vector<string> & files,
+BackendManagerRemoteTcp::get_remote_database(const std::vector<string> & files,
 					     unsigned int timeout)
 {
-    string args = get_remote_database_args(files, timeout);
+    std::string args = get_remote_database_args(files, timeout);
     int port = launch_xapian_tcpsrv(args);
     return Xapian::Remote::open(LOCALHOST, port);
 }
@@ -381,7 +381,7 @@
 Xapian::Database
 BackendManagerRemoteTcp::get_database_by_path(const string& path)
 {
-    string args = get_remote_database_args(path, 300000);
+    std::string args = get_remote_database_args(path, 300000);
     int port = launch_xapian_tcpsrv(args);
     return Xapian::Remote::open(LOCALHOST, port);
 }
@@ -389,7 +389,7 @@
 Xapian::Database
 BackendManagerRemoteTcp::get_writable_database_as_database()
 {
-    string args = get_writable_database_as_database_args();
+    std::string args = get_writable_database_as_database_args();
     int port = launch_xapian_tcpsrv(args);
     return Xapian::Remote::open(LOCALHOST, port);
 }
@@ -397,7 +397,7 @@
 Xapian::WritableDatabase
 BackendManagerRemoteTcp::get_writable_database_again()
 {
-    string args = get_writable_database_again_args();
+    std::string args = get_writable_database_again_args();
     int port = launch_xapian_tcpsrv(args);
     return Xapian::Remote::open_writable(LOCALHOST, port);
 }
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.h xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.h
--- xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_remotetcp.h	2022-11-08 16:44:01.048512805 +0100
@@ -47,7 +47,7 @@
 
     ~BackendManagerRemoteTcp();
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a RemoteTcp Xapian::WritableDatabase object indexing a single file.
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_singlefile.cc xapian-core-1.4.21/tests/harness/backendmanager_singlefile.cc
--- xapian-core-1.4.21/tests/harness/backendmanager_singlefile.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_singlefile.cc	2022-11-08 16:44:15.512461387 +0100
@@ -48,9 +48,9 @@
 }
 
 string
-BackendManagerSingleFile::do_get_database_path(const vector<string> & files)
+BackendManagerSingleFile::do_get_database_path(const std::vector<string> & files)
 {
-    string db_path = cachedir + "/db";
+    std::string db_path = cachedir + "/db";
     for (const string& file : files) {
 	db_path += "__";
 	db_path += file;
@@ -59,7 +59,7 @@
     if (!file_exists(db_path)) {
 	// No cached DB exists.  Create at a temporary path and rename
 	// so we don't leave a partial DB in place upon failure.
-	string tmp_path = db_path + ".tmp";
+	std::string tmp_path = db_path + ".tmp";
 	sub_manager->get_database(files).compact(tmp_path,
 						 Xapian::DBCOMPACT_SINGLE_FILE);
 	if (rename(tmp_path.c_str(), db_path.c_str()) < 0) {
@@ -71,7 +71,7 @@
 }
 
 Xapian::WritableDatabase
-BackendManagerSingleFile::get_writable_database(const string &, const string &)
+BackendManagerSingleFile::get_writable_database(const std::string &, const std::string &)
 {
     throw Xapian::UnimplementedError("Single-file databases don't support writing");
 }
diff -ur xapian-core-1.4.21/tests/harness/backendmanager_singlefile.h xapian-core-1.4.21/tests/harness/backendmanager_singlefile.h
--- xapian-core-1.4.21/tests/harness/backendmanager_singlefile.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/backendmanager_singlefile.h	2022-11-08 16:44:01.044512820 +0100
@@ -48,7 +48,7 @@
     BackendManagerSingleFile(const std::string& datadir_,
 			     BackendManager* sub_manager_);
 
-    /// Return a string representing the current database type.
+    /// Return a std::string representing the current database type.
     std::string get_dbtype() const;
 
     /// Create a Xapian::WritableDatabase object.
diff -ur xapian-core-1.4.21/tests/harness/fdtracker.cc xapian-core-1.4.21/tests/harness/fdtracker.cc
--- xapian-core-1.4.21/tests/harness/fdtracker.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/fdtracker.cc	2022-11-08 16:44:15.512461387 +0100
@@ -137,7 +137,7 @@
 	    continue;
 	}
 
-	string proc_symlink = FD_DIRECTORY "/";
+	std::string proc_symlink = FD_DIRECTORY "/";
 	proc_symlink += name;
 
 	char buf[1024];
diff -ur xapian-core-1.4.21/tests/harness/fdtracker.h xapian-core-1.4.21/tests/harness/fdtracker.h
--- xapian-core-1.4.21/tests/harness/fdtracker.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/fdtracker.h	2022-11-08 16:44:01.044512820 +0100
@@ -34,7 +34,7 @@
     /** Which fds are open.
      *
      *  The lowest unused fd is used whenever a new fd is needed so we
-     *  can expect them to form a dense set and vector<bool> should be an
+     *  can expect them to form a dense set and std::vector<bool> should be an
      *  efficient representation both in space and time.
      */
     std::vector<bool> fds;
diff -ur xapian-core-1.4.21/tests/harness/index_utils.cc xapian-core-1.4.21/tests/harness/index_utils.cc
--- xapian-core-1.4.21/tests/harness/index_utils.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/index_utils.cc	2022-11-08 16:44:15.508461401 +0100
@@ -32,13 +32,13 @@
 
 using namespace std;
 
-static string munge_term(const string &term);
+static std::string munge_term(const std::string &term);
 
 /// Read a paragraph from stream @a input.
 static string
 get_paragraph(istream &input)
 {
-    string para, line;
+    std::string para, line;
     while (true) {
 	getline(input, line);
 	if (find_if(line.begin(), line.end(), C_isnotspace) == line.end())
@@ -57,12 +57,12 @@
 	if (input.eof()) next_file();
 
 	Xapian::Document doc;
-	string para = get_paragraph(input);
+	std::string para = get_paragraph(input);
 	doc.set_data(para);
 
 	// Value 0 contains all possible character values so we can check that
 	// none of them cause problems.
-	string value0("X\0\0\0 \1\t"
+	std::string value0("X\0\0\0 \1\t"
 	    "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 	    "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
 	    "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
@@ -104,7 +104,7 @@
 	    string::const_iterator word_start;
 	    word_start = find_if(word_end, para_end, C_isnotspace);
 	    word_end = find_if(word_start, para_end, C_isspace);
-	    string word = stemmer(munge_term(string(word_start, word_end)));
+	    std::string word = stemmer(munge_term(string(word_start, word_end)));
 	    if (!word.empty()) doc.add_posting(word, ++pos);
 	}
 
@@ -114,9 +114,9 @@
 
 // Strip unwanted characters, force to lower case, and handle \ escapes.
 static string
-munge_term(const string &term)
+munge_term(const std::string &term)
 {
-    string result;
+    std::string result;
     for (string::const_iterator i = term.begin(); i != term.end(); ++i) {
 	char ch = *i;
 	if (C_isalnum(ch))
@@ -169,7 +169,7 @@
     }
     if (file == end) return;
 
-    string filename;
+    std::string filename;
     if (!datadir.empty()) {
 	filename = datadir;
 	bool need_slash = true;
@@ -187,7 +187,7 @@
     input.open(filename.c_str());
     // Need to check is_open() - just using operator! fails with MSVC.
     if (!input.is_open()) {
-	string msg = "Can't read file '";
+	std::string msg = "Can't read file '";
 	msg += filename;
 	msg += "' for indexing (";
 	errno_to_string(errno, msg);
diff -ur xapian-core-1.4.21/tests/harness/testrunner.cc xapian-core-1.4.21/tests/harness/testrunner.cc
--- xapian-core-1.4.21/tests/harness/testrunner.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/testrunner.cc	2022-11-08 16:44:15.516461372 +0100
@@ -44,7 +44,7 @@
 TestRunner::~TestRunner() { }
 
 bool
-TestRunner::use_backend(const string & backend_name)
+TestRunner::use_backend(const std::string & backend_name)
 {
     if (user_backend.empty())
 	return true;
@@ -56,7 +56,7 @@
 }
 
 void
-TestRunner::set_properties_for_backend(const string & backend_name)
+TestRunner::set_properties_for_backend(const std::string & backend_name)
 {
     /// A description of the properties which a particular backend supports.
     struct BackendProperties {
@@ -141,7 +141,7 @@
 	test_driver::add_command_line_option("backend", 'b', &user_backend);
 	test_driver::parse_command_line(argc, argv);
 	srcdir = test_driver::get_srcdir();
-	string datadir = srcdir + "/testdata/";
+	std::string datadir = srcdir + "/testdata/";
 
 	do_tests_for_backend(BackendManager(string()));
 
@@ -154,7 +154,7 @@
 	    BackendManagerGlass glass_man(datadir);
 
 	    // Vector for multi backendmanagers.
-	    vector<BackendManager*> multi_mans;
+	    std::vector<BackendManager*> multi_mans;
 	    multi_mans = {&glass_man, &glass_man};
 
 	    do_tests_for_backend(glass_man);
@@ -182,7 +182,7 @@
 	    BackendManagerChert chert_man(datadir);
 
 	    // Vector for multi backendmanagers.
-	    vector<BackendManager*> multi_mans;
+	    std::vector<BackendManager*> multi_mans;
 	    multi_mans = {&chert_man, &chert_man};
 
 #ifdef XAPIAN_HAS_CHERT_BACKEND
diff -ur xapian-core-1.4.21/tests/harness/testsuite.cc xapian-core-1.4.21/tests/harness/testsuite.cc
--- xapian-core-1.4.21/tests/harness/testsuite.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/testsuite.cc	2022-11-08 16:44:15.520461359 +0100
@@ -107,7 +107,7 @@
 test_driver::result test_driver::total;
 string test_driver::argv0;
 string test_driver::opt_help;
-map<int, string *> test_driver::short_opts;
+map<int, std::string *> test_driver::short_opts;
 vector<string> test_driver::test_names;
 bool test_driver::abort_on_error = false;
 string test_driver::col_red, test_driver::col_green;
@@ -117,7 +117,7 @@
 void
 test_driver::write_and_clear_tout()
 {
-    const string & s = tout.str();
+    const std::string & s = tout.str();
     if (!s.empty()) {
 	out << '\n' << s;
 	tout.str(string());
@@ -131,9 +131,9 @@
     if (p != NULL) return string(p);
 
     // Default srcdir to the pathname of argv[0].
-    string srcdir(argv0);
+    std::string srcdir(argv0);
     string::size_type i = srcdir.find_last_of(DIR_SEPS);
-    string srcfile;
+    std::string srcfile;
     if (i != string::npos) {
 	srcfile.assign(srcdir, i + 1, string::npos);
 	srcdir.erase(i);
@@ -433,7 +433,7 @@
 		    vg_dubious = vg_dubious2 - vg_dubious;
 		    vg_reachable = vg_reachable2 - vg_reachable;
 		    if (vg_errs) {
-			string fail_msg(buf);
+			std::string fail_msg(buf);
 			if (fail_msg.empty())
 			    fail_msg = "VALGRIND DETECTED A PROBLEM";
 			REPORT_FAIL_VG(fail_msg);
@@ -511,7 +511,7 @@
 #ifndef NO_LIBXAPIAN
 	    } catch (const Xapian::Error &err) {
 		out << ' ';
-		string errclass = err.get_type();
+		std::string errclass = err.get_type();
 		if (expected_exception && expected_exception == errclass) {
 		    out << col_yellow << "C++ FAILED TO CATCH " << errclass << col_reset;
 		    return SKIP;
@@ -538,7 +538,7 @@
 		write_and_clear_tout();
 		return expected_failure ? XFAIL : FAIL;
 #endif
-	    } catch (const string & msg) {
+	    } catch (const std::string & msg) {
 		out << ' ';
 		if (expected_failure) {
 		    out << col_yellow << "XFAIL (" << expected_failure
@@ -649,7 +649,7 @@
 
 test_driver::result
 test_driver::run_tests(vector<string>::const_iterator b,
-		       vector<string>::const_iterator e)
+		       std::vector<string>::const_iterator e)
 {
     return do_run_tests(b, e);
 }
@@ -657,13 +657,13 @@
 test_driver::result
 test_driver::run_tests()
 {
-    const vector<string> blank;
+    const std::vector<string> blank;
     return do_run_tests(blank.begin(), blank.end());
 }
 
 test_driver::result
 test_driver::do_run_tests(vector<string>::const_iterator b,
-			  vector<string>::const_iterator e)
+			  std::vector<string>::const_iterator e)
 {
     set<string> m(b, e);
     bool check_name = !m.empty();
@@ -677,7 +677,7 @@
 	if (!do_this_test) {
 	    // if this test is "foo123" see if "foo" was listed
 	    // this way "./testprog foo" can run foo1, foo2, etc.
-	    string t = test->name;
+	    std::string t = test->name;
 	    string::size_type i;
 	    i = t.find_last_not_of("0123456789") + 1;
 	    if (i != string::npos) {
@@ -751,7 +751,7 @@
 }
 
 void
-test_driver::report(const test_driver::result &r, const string &desc)
+test_driver::report(const test_driver::result &r, const std::string &desc)
 {
     // Report totals at the end if we reported two or more subtotals.
     if (++runs == 2) atexit(report_totals);
@@ -785,7 +785,7 @@
 }
 
 void
-test_driver::add_command_line_option(const string &l, char s, string * arg)
+test_driver::add_command_line_option(const std::string &l, char s, std::string * arg)
 {
     short_opts.insert(make_pair(int(s), arg));
     opt_help += "[-";
@@ -839,8 +839,8 @@
 	{NULL,			0, 0, 0}
     };
 
-    string short_opts_string = "voh";
-    map<int, string *>::const_iterator i;
+    std::string short_opts_string = "voh";
+    std::map<int, std::string *>::const_iterator i;
     for (i = short_opts.begin(); i != short_opts.end(); ++i) {
 	short_opts_string += char(i->first);
 	short_opts_string += ':';
diff -ur xapian-core-1.4.21/tests/harness/testsuite.h xapian-core-1.4.21/tests/harness/testsuite.h
--- xapian-core-1.4.21/tests/harness/testsuite.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/testsuite.h	2022-11-08 16:44:01.044512820 +0100
@@ -91,7 +91,7 @@
 //  expensive.
 extern int verbose;
 
-/** Set to a string explanation for testcases expected to fail. */
+/** Set to a std::string explanation for testcases expected to fail. */
 extern const char* expected_failure;
 
 /// The exception type we were expecting in TEST_EXCEPTION.
@@ -313,7 +313,7 @@
 
 /** Mark a testcase as expected to fail.
  *
- *  @param msg	An static string explaining why the testcase is expected to
+ *  @param msg	An static std::string explaining why the testcase is expected to
  *		fail.  Must not be NULL.
  *
  *  This is intended to be used temporarily to mark tests for known bugs before
diff -ur xapian-core-1.4.21/tests/harness/testutils.cc xapian-core-1.4.21/tests/harness/testutils.cc
--- xapian-core-1.4.21/tests/harness/testutils.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/testutils.cc	2022-11-08 16:44:15.516461372 +0100
@@ -32,7 +32,7 @@
 using namespace std;
 
 ostream &
-operator<<(ostream &os, const vector<Xapian::docid> &ints)
+operator<<(ostream &os, const std::vector<Xapian::docid> &ints)
 {
     copy(ints.begin(), ints.end(),
 	 ostream_iterator<Xapian::docid>(os, ", "));
@@ -80,7 +80,7 @@
 
 bool
 mset_range_is_same(const Xapian::MSet& mset, unsigned int first,
-		   const pair<Xapian::docid, double> to_compare[],
+		   const std::pair<Xapian::docid, double> to_compare[],
 		   unsigned int count)
 {
     TEST_AND_EXPLAIN(mset.size() >= first + count - 1,
@@ -157,7 +157,7 @@
 		   Xapian::docid d5, Xapian::docid d6, Xapian::docid d7, Xapian::docid d8,
 		   Xapian::docid d9, Xapian::docid d10, Xapian::docid d11, Xapian::docid d12)
 {
-    vector<Xapian::docid> expect;
+    std::vector<Xapian::docid> expect;
     if (d1) {
 	expect.push_back(d1);
 	if (d2) {
diff -ur xapian-core-1.4.21/tests/harness/unixcmds.cc xapian-core-1.4.21/tests/harness/unixcmds.cc
--- xapian-core-1.4.21/tests/harness/unixcmds.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/harness/unixcmds.cc	2022-11-08 16:44:15.512461387 +0100
@@ -51,11 +51,11 @@
 
 /// Call system() and throw exception if it fails.
 static void
-checked_system(const string & cmd)
+checked_system(const std::string & cmd)
 {
     int res = system(cmd.c_str());
     if (res) {
-	string msg = "system(\"";
+	std::string msg = "system(\"";
 	msg += cmd;
 	msg += "\") failed, returning ";
 	msg += str(res);
@@ -70,9 +70,9 @@
     // whether we want to create a directory or a file (which makes no sense
     // when copying a directory, but that's how xcopy seems to work!)
     mkdir(dest.c_str());
-    string cmd("xcopy /E /q /Y");
+    std::string cmd("xcopy /E /q /Y");
 #else
-    string cmd("cp -R");
+    std::string cmd("cp -R");
 #endif
     if (!append_filename_argument(cmd, src)) return;
     if (!append_filename_argument(cmd, dest)) return;
@@ -108,7 +108,7 @@
 #endif
 
 /// Remove a directory and contents, just like the Unix "rm -rf" command.
-void rm_rf(const string &filename) {
+void rm_rf(const std::string &filename) {
     // Check filename exists and is actually a directory
     if (filename.empty() || !dir_exists(filename))
 	return;
@@ -126,7 +126,7 @@
 	if (eno < 0)
 	    eno = errno;
 	if (!(eno == EEXIST || eno == ENOTEMPTY) || --retries == 0) {
-	    string msg = "recursive delete of \"";
+	    std::string msg = "recursive delete of \"";
 	    msg += filename;
 	    msg += "\") failed, errno = ";
 	    errno_to_string(eno, msg);
@@ -142,9 +142,9 @@
     }
 #else
 # ifdef __WIN32__
-    string cmd("rd /s /q");
+    std::string cmd("rd /s /q");
 # else
-    string cmd("rm -rf");
+    std::string cmd("rm -rf");
 # endif
     if (!append_filename_argument(cmd, filename)) return;
     checked_system(cmd);
@@ -152,7 +152,7 @@
 }
 
 /// Touch a file, just like the Unix "touch" command.
-void touch(const string &filename) {
+void touch(const std::string &filename) {
     int fd = open(filename.c_str(), O_CREAT|O_WRONLY|O_BINARY, 0644);
     if (fd >= 0) close(fd);
 }
diff -ur xapian-core-1.4.21/tests/internaltest.cc xapian-core-1.4.21/tests/internaltest.cc
--- xapian-core-1.4.21/tests/internaltest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/internaltest.cc	2022-11-08 16:44:15.556461230 +0100
@@ -205,11 +205,11 @@
     TEST(deleted);
 }
 
-// test string comparisons
+// test std::string comparisons
 static void test_stringcomp1()
 {
-    string s1;
-    string s2;
+    std::string s1;
+    std::string s2;
 
     s1 = "foo";
     s2 = "foo";
@@ -263,9 +263,9 @@
 /// Test pack_uint_preserving_sort()
 static void test_pack_uint_preserving_sort1()
 {
-    string prev_packed;
+    std::string prev_packed;
     for (unsigned int i = 0; i != 1000; ++i) {
-	string packed;
+	std::string packed;
 	pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -277,7 +277,7 @@
 	swap(prev_packed, packed);
     }
     for (unsigned int i = 2345; i < 65000; i += 113) {
-	string packed;
+	std::string packed;
 	pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -290,7 +290,7 @@
     }
     unsigned int prev = 64999;
     for (unsigned int i = 65000; i > prev; prev = i, i = (i << 1) ^ 1337) {
-	string packed;
+	std::string packed;
 	pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -303,7 +303,7 @@
     }
 
     /* Test packing multiple numbers to one string. */
-    string packed;
+    std::string packed;
     for (unsigned int i = 23456; i < 765432; i += 1131) {
 	pack_uint_preserving_sort(packed, i);
     }
@@ -320,9 +320,9 @@
 /// Test C_pack_uint_preserving_sort()
 static void test_pack_uint_preserving_sort2()
 {
-    string prev_packed;
+    std::string prev_packed;
     for (unsigned int i = 0; i != 1000; ++i) {
-	string packed;
+	std::string packed;
 	C_pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -334,7 +334,7 @@
 	swap(prev_packed, packed);
     }
     for (unsigned int i = 2345; i < 65000; i += 113) {
-	string packed;
+	std::string packed;
 	C_pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -347,7 +347,7 @@
     }
     unsigned int prev = 64999;
     for (unsigned int i = 65000; i > prev; prev = i, i = (i << 1) ^ 1337) {
-	string packed;
+	std::string packed;
 	C_pack_uint_preserving_sort(packed, i);
 	const char * ptr = packed.data();
 	const char * end = ptr + packed.size();
@@ -360,7 +360,7 @@
     }
 
     /* Test packing multiple numbers to one string. */
-    string packed;
+    std::string packed;
     for (unsigned int i = 23456; i < 765432; i += 1131) {
 	C_pack_uint_preserving_sort(packed, i);
     }
diff -ur xapian-core-1.4.21/tests/perftest/perftest.cc xapian-core-1.4.21/tests/perftest/perftest.cc
--- xapian-core-1.4.21/tests/perftest/perftest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/perftest/perftest.cc	2022-11-08 16:44:15.540461287 +0100
@@ -52,9 +52,9 @@
 PerfTestLogger logger;
 
 static string
-escape_xml(const string & str)
+escape_xml(const std::string & str)
 {
-    string res;
+    std::string res;
     string::size_type p = 0;
     while (p < str.size()) {
 	char ch = str[p++];
@@ -131,7 +131,7 @@
 #ifdef __WIN32__
     return string();
 #else
-    string loadavg;
+    std::string loadavg;
     try {
 	loadavg = stdout_to_string("uptime 2>/dev/null | sed 's/.*: \$[0-9][0-9]*\$/\\1/;s/, .*//'");
     } catch (const NoSuchProgram&) {
@@ -145,7 +145,7 @@
 static string
 get_ncpus()
 {
-    string ncpus;
+    std::string ncpus;
 #ifdef __WIN32__
     SYSTEM_INFO siSysInfo;
     GetSystemInfo(&siSysInfo);
@@ -188,7 +188,7 @@
 static string
 get_distro()
 {
-    string distro;
+    std::string distro;
 #ifdef __WIN32__
     OSVERSIONINFO osvi;
     ZeroMemory(&osvi, sizeof(OSVERSIONINFO));
@@ -214,7 +214,7 @@
 static string
 get_commit_ref()
 {
-    string commit_ref;
+    std::string commit_ref;
     try {
 	commit_ref = stdout_to_string("cd \"$srcdir\" && git log -n1 --abbrev-commit --format=%h");
     } catch (const NoSuchProgram&) {
@@ -225,7 +225,7 @@
 }
 
 bool
-PerfTestLogger::open(const string & logpath)
+PerfTestLogger::open(const std::string & logpath)
 {
     out.open(logpath.c_str(), ios::out | ios::binary | ios::trunc);
     if (!out.is_open()) {
@@ -233,10 +233,10 @@
 	return false;
     }
 
-    string loadavg = get_loadavg();
-    string hostname = get_hostname();
-    string ncpus = get_ncpus();
-    string distro = get_distro();
+    std::string loadavg = get_loadavg();
+    std::string hostname = get_hostname();
+    std::string ncpus = get_ncpus();
+    std::string distro = get_distro();
 
     // Write header, and details of the machine.
     write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<testrun>\n"
@@ -252,7 +252,7 @@
     write("  <physmem>" + str(get_total_physical_memory()) + "</physmem>\n");
     write(" </machineinfo>\n");
 
-    const string & commit_ref = get_commit_ref();
+    const std::string & commit_ref = get_commit_ref();
 
     write(" <sourceinfo>\n");
     if (!commit_ref.empty())
@@ -264,7 +264,7 @@
 }
 
 void
-PerfTestLogger::write(const string & text)
+PerfTestLogger::write(const std::string & text)
 {
     out.write(text.data(), text.size());
     out.flush();
@@ -281,7 +281,7 @@
 }
 
 void
-PerfTestLogger::indexing_begin(const string & dbname,
+PerfTestLogger::indexing_begin(const std::string & dbname,
 			       const std::map<std::string, std::string> & params)
 {
     searching_end();
@@ -352,7 +352,7 @@
 }
 
 void
-PerfTestLogger::searching_start(const string & description)
+PerfTestLogger::searching_start(const std::string & description)
 {
     indexing_end();
     searching_end();
@@ -397,7 +397,7 @@
 }
 
 void
-PerfTestLogger::testcase_begin(const string & testcase)
+PerfTestLogger::testcase_begin(const std::string & testcase)
 {
     testcase_end();
     write(" <testcase name=\"" + testcase + "\" backend=\"" +
@@ -432,7 +432,7 @@
 
 class PerfTestRunner : public TestRunner
 {
-    string repetitions_string;
+    std::string repetitions_string;
     mutable bool repetitions_parsed;
     mutable int repetitions;
   public:
diff -ur xapian-core-1.4.21/tests/perftest/perftest_matchdecider.cc xapian-core-1.4.21/tests/perftest/perftest_matchdecider.cc
--- xapian-core-1.4.21/tests/perftest/perftest_matchdecider.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/perftest/perftest_matchdecider.cc	2022-11-08 16:44:15.540461287 +0100
@@ -36,7 +36,7 @@
 using namespace std;
 
 static void
-builddb_valuestest1(Xapian::WritableDatabase &db, const string & dbname)
+builddb_valuestest1(Xapian::WritableDatabase &db, const std::string & dbname)
 {
     logger.testcase_begin(dbname);
     unsigned int runsize = 1000000;
@@ -50,7 +50,7 @@
 	Xapian::Document doc;
 	doc.set_data("test document " + str(i));
 	doc.add_term("foo");
-	string vs = str(v);
+	std::string vs = str(v);
 	if (vs.size() == 1) vs = "0" + vs;
 	doc.add_value(0, vs);
 	doc.add_term("F" + vs);
@@ -95,7 +95,7 @@
     Xapian::ValueSetMatchDecider md(0, true);
 
     for (unsigned int i = 0; i < 100; ++i) {
-	string vs = str(i);
+	std::string vs = str(i);
 	if (vs.size() == 1) vs = "0" + vs;
 	md.add_value(vs);
 
diff -ur xapian-core-1.4.21/tests/perftest/perftest_randomidx.cc xapian-core-1.4.21/tests/perftest/perftest_randomidx.cc
--- xapian-core-1.4.21/tests/perftest/perftest_randomidx.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/perftest/perftest_randomidx.cc	2022-11-08 16:44:15.540461287 +0100
@@ -69,7 +69,7 @@
 static string
 gen_word(unsigned int length, unsigned int char_range)
 {
-    string result;
+    std::string result;
     result.reserve(length);
     for (unsigned int i = 0; i != length; ++i) {
 	char ch = char('a' + rand_int(char_range));
diff -ur xapian-core-1.4.21/tests/perftest/runprocess.cc xapian-core-1.4.21/tests/perftest/runprocess.cc
--- xapian-core-1.4.21/tests/perftest/runprocess.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/perftest/runprocess.cc	2022-11-08 16:44:15.540461287 +0100
@@ -36,9 +36,9 @@
 using namespace std;
 
 string
-stdout_to_string(const string &cmd)
+stdout_to_string(const std::string &cmd)
 {
-    string out;
+    std::string out;
     FILE * fh = popen(cmd.c_str(), "r");
     if (fh == NULL) throw ReadError();
     while (!feof(fh)) {
diff -ur xapian-core-1.4.21/tests/soaktest/soaktest.cc xapian-core-1.4.21/tests/soaktest/soaktest.cc
--- xapian-core-1.4.21/tests/soaktest/soaktest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/soaktest/soaktest.cc	2022-11-08 16:44:15.484461486 +0100
@@ -62,7 +62,7 @@
 
 class SoakTestRunner : public TestRunner
 {
-    string seed_str;
+    std::string seed_str;
   public:
     SoakTestRunner() : seed_str("42") {
 	test_driver::add_command_line_option("seed", 's', &seed_str);
diff -ur xapian-core-1.4.21/tests/soaktest/soaktest_queries.cc xapian-core-1.4.21/tests/soaktest/soaktest_queries.cc
--- xapian-core-1.4.21/tests/soaktest/soaktest_queries.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/soaktest/soaktest_queries.cc	2022-11-08 16:44:15.484461486 +0100
@@ -43,7 +43,7 @@
  *  contains all Nx for x from 1 to randint(maxtermsperfield).
  */
 static void
-builddb_queries1(Xapian::WritableDatabase &db, const string &arg)
+builddb_queries1(Xapian::WritableDatabase &db, const std::string &arg)
 {
     unsigned int doccount = 1000;
     unsigned int maxtermsperfield = atoi(arg.c_str());
@@ -60,7 +60,7 @@
 /// The environment used by the steps when building a query.
 struct QueryBuilderEnv {
     /// Workspace for the query builder steps.
-    list<Xapian::Query> pieces;
+    std::list<Xapian::Query> pieces;
 
     unsigned int maxtermsperfield;
     unsigned int maxchildren;
@@ -80,7 +80,7 @@
     }
 
     /// Get an iterator pointing to the "num"th element in pieces.
-    list<Xapian::Query>::iterator pick(unsigned int num) {
+    std::list<Xapian::Query>::iterator pick(unsigned int num) {
 	list<Xapian::Query>::iterator i = pieces.begin();
 	for (unsigned int c = 0; c != num && i != pieces.end(); ++c, ++i) {}
 	return i;
@@ -103,7 +103,7 @@
  */
 static void combine_OR(QueryBuilderEnv & env)
 {
-    list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
+    std::list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
     Xapian::Query combined(Xapian::Query::OP_OR, env.pieces.begin(), i);
     env.pieces.erase(env.pieces.begin(), i);
     env.pieces.push_back(combined);
@@ -116,7 +116,7 @@
  */
 static void combine_AND(QueryBuilderEnv & env)
 {
-    list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
+    std::list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
     Xapian::Query combined(Xapian::Query::OP_AND, env.pieces.begin(), i);
     env.pieces.erase(env.pieces.begin(), i);
     env.pieces.push_back(combined);
@@ -129,7 +129,7 @@
  */
 static void combine_XOR(QueryBuilderEnv & env)
 {
-    list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
+    std::list<Xapian::Query>::iterator i = env.pick(randint(env.maxchildren));
     Xapian::Query combined(Xapian::Query::OP_XOR, env.pieces.begin(), i);
     env.pieces.erase(env.pieces.begin(), i);
     env.pieces.push_back(combined);
@@ -143,7 +143,7 @@
 static void combine_NOT(QueryBuilderEnv & env)
 {
     if (env.pieces.size() < 2) return;
-    list<Xapian::Query>::iterator i = env.pick(2);
+    std::list<Xapian::Query>::iterator i = env.pick(2);
     Xapian::Query combined(Xapian::Query::OP_AND_NOT, env.pieces.begin(), i);
     env.pieces.erase(env.pieces.begin(), i);
     env.pieces.push_back(combined);
@@ -152,7 +152,7 @@
 /// Random query builder.
 class QueryBuilder {
     /// The possible steps.
-    vector<QueryStep> options;
+    std::vector<QueryStep> options;
 
     /// The environment for the build steps.
     QueryBuilderEnv env;
@@ -208,7 +208,7 @@
     QueryBuilder builder(maxtermsperfield, 10, 10);
 
     Xapian::Database db;
-    string arg(str(maxtermsperfield));
+    std::string arg(str(maxtermsperfield));
     db = backendmanager->get_database("queries1_" + str(seed) + "_" + arg,
 				      builddb_queries1, arg);
 
diff -ur xapian-core-1.4.21/tests/stemtest.cc xapian-core-1.4.21/tests/stemtest.cc
--- xapian-core-1.4.21/tests/stemtest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/stemtest.cc	2022-11-08 16:44:15.492461458 +0100
@@ -36,11 +36,11 @@
 
 static const int JUNKSIZE = 2 * 1048576;
 
-static string language;
+static std::string language;
 
 static Xapian::Stem stemmer;
 
-static string srcdir;
+static std::string srcdir;
 
 static int seed;
 
@@ -54,7 +54,7 @@
     tout << "Stemming random text... (seed " << seed << ")" << endl;
     srand(seed);
 
-    string word;
+    std::string word;
     int stemmed_size = 0;
     for (int c = JUNKSIZE; c; --c) {
 	char ch = wordchars[(rand() >> 8) % sizeof wordchars];
@@ -86,7 +86,7 @@
     tout << "Stemming random junk... (seed " << seed << ")" << endl;
     srand(seed);
 
-    string word;
+    std::string word;
     int stemmed_size = 0;
     for (int c = JUNKSIZE; c; --c) {
 	char ch = char(rand() >> 8);
@@ -114,7 +114,7 @@
 static void
 test_stemdict()
 {
-    string dir = srcdir + "/../../xapian-data/stemming/";
+    std::string dir = srcdir + "/../../xapian-data/stemming/";
 
     ifstream voc((dir + language + "/voc.txt").c_str());
     if (!voc.is_open()) {
@@ -131,7 +131,7 @@
 
     int pass = 1;
     while (true) {
-	string word, stem, expect;
+	std::string word, stem, expect;
 	while (!voc.eof() && !st.eof()) {
 	    getline(voc, word);
 	    getline(st, expect);
@@ -173,11 +173,11 @@
 
 int main(int argc, char **argv)
 try {
-    string langs = Xapian::Stem::get_available_languages();
+    std::string langs = Xapian::Stem::get_available_languages();
     test_driver::add_command_line_option("languages", 'l', &langs);
 
     seed = 42;
-    string seed_str;
+    std::string seed_str;
     test_driver::add_command_line_option("seed", 's', &seed_str);
 
     test_driver::parse_command_line(argc, argv);
diff -ur xapian-core-1.4.21/tests/unittest.cc xapian-core-1.4.21/tests/unittest.cc
--- xapian-core-1.4.21/tests/unittest.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/tests/unittest.cc	2022-11-08 16:44:15.536461302 +0100
@@ -120,7 +120,7 @@
 }
 
 static inline string
-r_r_p(string a, const string & b)
+r_r_p(string a, const std::string & b)
 {
     resolve_relative_path(a, b);
     return a;
@@ -202,13 +202,13 @@
 static void
 check_double_serialisation(double u)
 {
-    // Commonly C++ string implementations keep the string nul-terminated, and
+    // Commonly C++ std::string implementations keep the std::string nul-terminated, and
     // encoded.data() returns a pointer to a buffer including the nul (the same
     // as encoded.c_str()).  This means that valgrind won't catch a read one
     // past the end of the serialised value, so we copy just the serialised
     // value into a temporary buffer.
     char buf[16];
-    string encoded = serialise_double(u);
+    std::string encoded = serialise_double(u);
     TEST(encoded.size() < sizeof(buf));
     memcpy(buf, encoded.data(), encoded.size());
     // Put a NULL pointer either side, to catch incrementing/decrementing at
@@ -262,7 +262,7 @@
 {
     size_t n = 0;
     while (n < 0xff000000) {
-	string s = encode_length(n);
+	std::string s = encode_length(n);
 	const char *p = s.data();
 	const char *p_end = p + s.size();
 	size_t decoded_n;
@@ -283,7 +283,7 @@
 {
     // Special case tests for 0
     {
-	string s = encode_length(0);
+	std::string s = encode_length(0);
 	{
 	    const char *p = s.data();
 	    const char *p_end = p + s.size();
@@ -304,7 +304,7 @@
     }
     // Special case tests for 1
     {
-	string s = encode_length(1);
+	std::string s = encode_length(1);
 	TEST_EXCEPTION(Xapian_NetworkError,
 	    const char *p = s.data();
 	    const char *p_end = p + s.size();
@@ -333,7 +333,7 @@
     }
     // Nothing magic here, just test a range of odd and even values.
     for (size_t n = 2; n < 1000; n = (n + 1) * 2 + (n >> 1)) {
-	string s = encode_length(n);
+	std::string s = encode_length(n);
 	TEST_EXCEPTION(Xapian_NetworkError,
 	    const char *p = s.data();
 	    const char *p_end = p + s.size();
@@ -373,7 +373,7 @@
 // Check serialisation of Xapian::Error.
 static void test_serialiseerror1()
 {
-    string enoent_msg = errno_to_string(ENOENT);
+    std::string enoent_msg = errno_to_string(ENOENT);
     Xapian::DatabaseOpeningError e("Failed to open database", ENOENT);
     // Regression test for bug in 1.0.0 - it didn't convert errno values for
     // get_description() if they hadn't already been converted.
@@ -381,7 +381,7 @@
 
     TEST_STRINGS_EQUAL(e.get_error_string(), enoent_msg);
 
-    string serialisation = serialise_error(e);
+    std::string serialisation = serialise_error(e);
 
     // Test if unserialise_error() throws with a flag to avoid the possibility
     // of an "unreachable code" warning when we get around to marking
@@ -473,12 +473,12 @@
 static void test_sortableserialise1()
 {
     double prevnum = 0;
-    string prevstr;
+    std::string prevstr;
     bool started = false;
     for (const double *p = test_sortableserialise_numbers; *p != 64; ++p) {
 	double num = *p;
 	tout << "Number: " << num << '\n';
-	string str = Xapian::sortable_serialise(num);
+	std::string str = Xapian::sortable_serialise(num);
 	tout << "String: " << str << '\n';
 	TEST_EQUAL(Xapian::sortable_unserialise(str), num);
 
@@ -498,7 +498,7 @@
 
 	    TEST_AND_EXPLAIN(num_cmp == str_cmp,
 			     "Numbers " << prevnum << " and " << num <<
-			     " don't sort the same way as their string "
+			     " don't sort the same way as their std::string "
 			     "counterparts");
 	}
 
@@ -603,7 +603,7 @@
     // Test a generated uuid.
     uuid.generate();
     TEST(!uuid.is_null());
-    string str = uuid.to_string();
+    std::string str = uuid.to_string();
     TEST_EQUAL(str.size(), 36);
     TEST_NOT_EQUAL(str, "00000000-0000-0000-0000-000000000000");
     // Check UUID pattern is correct and that upper case is not used.
diff -ur xapian-core-1.4.21/unicode/description_append.cc xapian-core-1.4.21/unicode/description_append.cc
--- xapian-core-1.4.21/unicode/description_append.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/unicode/description_append.cc	2022-11-08 16:44:15.604461060 +0100
@@ -1,5 +1,5 @@
 /** @file
- *  @brief Append a string to an object description, escaping invalid UTF-8
+ *  @brief Append a std::string to an object description, escaping invalid UTF-8
  */
 /* Copyright (C) 2013,2019 Olly Betts
  *
diff -ur xapian-core-1.4.21/unicode/description_append.h xapian-core-1.4.21/unicode/description_append.h
--- xapian-core-1.4.21/unicode/description_append.h	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/unicode/description_append.h	2022-11-08 16:44:01.108512592 +0100
@@ -1,5 +1,5 @@
 /** @file
- *  @brief Append a string to an object description, escaping invalid UTF-8
+ *  @brief Append a std::string to an object description, escaping invalid UTF-8
  */
 /* Copyright (C) 2013 Olly Betts
  *
diff -ur xapian-core-1.4.21/weight/bb2weight.cc xapian-core-1.4.21/weight/bb2weight.cc
--- xapian-core-1.4.21/weight/bb2weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/bb2weight.cc	2022-11-08 16:44:15.428461685 +0100
@@ -129,7 +129,7 @@
 }
 
 BB2Weight *
-BB2Weight::unserialise(const string & s) const
+BB2Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/bm25plusweight.cc xapian-core-1.4.21/weight/bm25plusweight.cc
--- xapian-core-1.4.21/weight/bm25plusweight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/bm25plusweight.cc	2022-11-08 16:44:15.424461700 +0100
@@ -85,7 +85,7 @@
 string
 BM25PlusWeight::serialise() const
 {
-    string result = serialise_double(param_k1);
+    std::string result = serialise_double(param_k1);
     result += serialise_double(param_k2);
     result += serialise_double(param_k3);
     result += serialise_double(param_b);
@@ -95,7 +95,7 @@
 }
 
 BM25PlusWeight *
-BM25PlusWeight::unserialise(const string & s) const
+BM25PlusWeight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/bm25weight.cc xapian-core-1.4.21/weight/bm25weight.cc
--- xapian-core-1.4.21/weight/bm25weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/bm25weight.cc	2022-11-08 16:44:15.420461713 +0100
@@ -137,7 +137,7 @@
 string
 BM25Weight::serialise() const
 {
-    string result = serialise_double(param_k1);
+    std::string result = serialise_double(param_k1);
     result += serialise_double(param_k2);
     result += serialise_double(param_k3);
     result += serialise_double(param_b);
@@ -146,7 +146,7 @@
 }
 
 BM25Weight *
-BM25Weight::unserialise(const string & s) const
+BM25Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/ifb2weight.cc xapian-core-1.4.21/weight/ifb2weight.cc
--- xapian-core-1.4.21/weight/ifb2weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/ifb2weight.cc	2022-11-08 16:44:15.428461685 +0100
@@ -103,7 +103,7 @@
 }
 
 IfB2Weight *
-IfB2Weight::unserialise(const string & s) const
+IfB2Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/ineb2weight.cc xapian-core-1.4.21/weight/ineb2weight.cc
--- xapian-core-1.4.21/weight/ineb2weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/ineb2weight.cc	2022-11-08 16:44:15.432461672 +0100
@@ -102,7 +102,7 @@
 }
 
 IneB2Weight *
-IneB2Weight::unserialise(const string & s) const
+IneB2Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/inl2weight.cc xapian-core-1.4.21/weight/inl2weight.cc
--- xapian-core-1.4.21/weight/inl2weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/inl2weight.cc	2022-11-08 16:44:15.432461672 +0100
@@ -100,7 +100,7 @@
 }
 
 InL2Weight *
-InL2Weight::unserialise(const string & s) const
+InL2Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/lmweight.cc xapian-core-1.4.21/weight/lmweight.cc
--- xapian-core-1.4.21/weight/lmweight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/lmweight.cc	2022-11-08 16:44:15.420461713 +0100
@@ -99,7 +99,7 @@
 string
 LMWeight::serialise() const
 {
-    string result = serialise_double(param_log);
+    std::string result = serialise_double(param_log);
     result += static_cast<unsigned char>(select_smoothing);
     result += serialise_double(param_smoothing1);
     result += serialise_double(param_smoothing2);
@@ -107,7 +107,7 @@
 }
 
 LMWeight *
-LMWeight::unserialise(const string & s) const
+LMWeight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/pl2plusweight.cc xapian-core-1.4.21/weight/pl2plusweight.cc
--- xapian-core-1.4.21/weight/pl2plusweight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/pl2plusweight.cc	2022-11-08 16:44:15.428461685 +0100
@@ -141,13 +141,13 @@
 string
 PL2PlusWeight::serialise() const
 {
-    string result = serialise_double(param_c);
+    std::string result = serialise_double(param_c);
     result += serialise_double(param_delta);
     return result;
 }
 
 PL2PlusWeight *
-PL2PlusWeight::unserialise(const string & s) const
+PL2PlusWeight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/pl2weight.cc xapian-core-1.4.21/weight/pl2weight.cc
--- xapian-core-1.4.21/weight/pl2weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/pl2weight.cc	2022-11-08 16:44:15.428461685 +0100
@@ -141,7 +141,7 @@
 }
 
 PL2Weight *
-PL2Weight::unserialise(const string & s) const
+PL2Weight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/tfidfweight.cc xapian-core-1.4.21/weight/tfidfweight.cc
--- xapian-core-1.4.21/weight/tfidfweight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/tfidfweight.cc	2022-11-08 16:44:15.424461700 +0100
@@ -42,7 +42,7 @@
 	!strchr("nbslL", normalizations[0]) ||
 	!strchr("ntpfs", normalizations[1]) ||
 	!strchr("n", normalizations[2]))
-	throw Xapian::InvalidArgumentError("Normalization string is invalid");
+	throw Xapian::InvalidArgumentError("Normalization std::string is invalid");
     if (normalizations[1] != 'n') {
 	need_stat(TERMFREQ);
 	need_stat(COLLECTION_SIZE);
@@ -89,7 +89,7 @@
 }
 
 TfIdfWeight *
-TfIdfWeight::unserialise(const string & s) const
+TfIdfWeight::unserialise(const std::string & s) const
 {
     if (s.length() != 3)
 	throw Xapian::SerialisationError("Extra data in TfIdfWeight::unserialise()");
diff -ur xapian-core-1.4.21/weight/tradweight.cc xapian-core-1.4.21/weight/tradweight.cc
--- xapian-core-1.4.21/weight/tradweight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/tradweight.cc	2022-11-08 16:44:15.424461700 +0100
@@ -136,7 +136,7 @@
 }
 
 TradWeight *
-TradWeight::unserialise(const string & s) const
+TradWeight::unserialise(const std::string & s) const
 {
     const char *ptr = s.data();
     const char *end = ptr + s.size();
diff -ur xapian-core-1.4.21/weight/weight.cc xapian-core-1.4.21/weight/weight.cc
--- xapian-core-1.4.21/weight/weight.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/weight.cc	2022-11-08 16:44:15.424461700 +0100
@@ -58,7 +58,7 @@
 
 void
 Weight::init_(const Internal & stats, Xapian::termcount query_length,
-	      const string & term, Xapian::termcount wqf, double factor,
+	      const std::string & term, Xapian::termcount wqf, double factor,
 	      void* postlist_void)
 {
     LOGCALL_VOID(MATCH, "Weight::init_", stats | query_length | term | wqf | factor | postlist_void);
@@ -91,7 +91,7 @@
 
 void
 Weight::init_(const Internal & stats, Xapian::termcount query_length,
-	      const string & term, Xapian::termcount wqf, double factor)
+	      const std::string & term, Xapian::termcount wqf, double factor)
 {
     init_(stats, query_length, term, wqf, factor, nullptr);
 }
@@ -144,7 +144,7 @@
 }
 
 Weight *
-Weight::unserialise(const string &) const
+Weight::unserialise(const std::string &) const
 {
     throw Xapian::UnimplementedError("unserialise() not supported for this Xapian::Weight subclass");
 }
diff -ur xapian-core-1.4.21/weight/weightinternal.cc xapian-core-1.4.21/weight/weightinternal.cc
--- xapian-core-1.4.21/weight/weightinternal.cc	2022-09-22 07:27:36.000000000 +0200
+++ xapian-core-1.4.21/weight/weightinternal.cc	2022-11-08 16:44:15.416461728 +0100
@@ -37,7 +37,7 @@
 
 string
 TermFreqs::get_description() const {
-    string desc("TermFreqs(termfreq=");
+    std::string desc("TermFreqs(termfreq=");
     desc += str(termfreq);
     desc += ", reltermfreq=";
     desc += str(reltermfreq);
@@ -63,7 +63,7 @@
     rset_size += inc.rset_size;
 
     // Add termfreqs and reltermfreqs
-    map<string, TermFreqs>::const_iterator i;
+    std::map<string, TermFreqs>::const_iterator i;
     for (i = inc.termfreqs.begin(); i != inc.termfreqs.end(); ++i) {
 	termfreqs[i->first] += i->second;
     }
@@ -84,7 +84,7 @@
 
     Xapian::TermIterator t;
     for (t = query.get_unique_terms_begin(); t != Xapian::TermIterator(); ++t) {
-	const string & term = *t;
+	const std::string & term = *t;
 
 	Xapian::doccount sub_tf;
 	Xapian::termcount sub_cf;
@@ -103,9 +103,9 @@
 	// and we can skip the document's termlist, so look for each query term
 	// in the document.
 	AutoPtr<TermList> tl(subdb.open_term_list(did));
-	map<string, TermFreqs>::iterator i;
+	std::map<string, TermFreqs>::iterator i;
 	for (i = termfreqs.begin(); i != termfreqs.end(); ++i) {
-	    const string & term = i->first;
+	    const std::string & term = i->first;
 	    TermList * ret = tl->skip_to(term);
 	    Assert(ret == NULL);
 	    (void)ret;
@@ -130,7 +130,7 @@
 string
 Weight::Internal::get_description() const
 {
-    string desc = "Weight::Internal(totlen=";
+    std::string desc = "Weight::Internal(totlen=";
     desc += str(total_length);
     desc += ", collection_size=";
     desc += str(collection_size);
@@ -143,7 +143,7 @@
     desc += str(finalised);
 #endif
     desc += ", termfreqs={";
-    map<string, TermFreqs>::const_iterator i;
+    std::map<string, TermFreqs>::const_iterator i;
     for (i = termfreqs.begin(); i != termfreqs.end(); ++i) {
 	if (i != termfreqs.begin())
 	    desc += ", ";

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File xapian-core-1.4.21-std-fixes.patch of Package mingw32-xapian-core (Revision d711f460150d0eaec24247edfa2d3d43)

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