File otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm.patch of Package erlang

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File otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm.patch of Package erlang (Revision 58ddfd9fcf4c281c82656d8c2d2a71df)

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diff -Ndurp otp_src_23.3.4.20/lib/stdlib/doc/src/gen_fsm.xml otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm/lib/stdlib/doc/src/gen_fsm.xml
--- otp_src_23.3.4.20/lib/stdlib/doc/src/gen_fsm.xml	2024-03-14 09:08:00.000000000 +0200
+++ otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm/lib/stdlib/doc/src/gen_fsm.xml	2024-09-26 01:02:55.147989254 +0300
@@ -29,11 +29,924 @@
 <rev></rev>
 </header>
 <module>gen_fsm</module>
- <modulesummary>Deprecated and replaced by gen_statem </modulesummary>
-
+ <modulesummary>Generic finite state machine behavior.</modulesummary>
 <description>
- Deprecated and replaced by <seeerl marker="gen_statem"><c>gen_statem</c></seeerl> 
+ <note>
+ 
+	There is a new behaviour
+	<seeerl marker="gen_statem"><c>gen_statem</c></seeerl>
+	that is intended to replace <c>gen_fsm</c> for new code.
+	<c>gen_fsm</c> will not be removed for the foreseeable future
+	to keep old state machine implementations running.
+ 
+ </note>
+ This behavior module provides a finite state machine.
+ A generic finite state machine process (<c>gen_fsm</c>) implemented
+ using this module has a standard set of interface functions
+ and includes functionality for tracing and error reporting. It
+ also fits into an OTP supervision tree. For more information, see
+ <seeguide marker="doc/design_principles:fsm">OTP Design Principles</seeguide>.
+ 
+
+ A <c>gen_fsm</c> process assumes all specific parts to be located in a
+ callback module exporting a predefined set of functions. The relationship
+ between the behavior functions and the callback functions is as
+ follows:
+
+ <pre>
+gen_fsm module Callback module
+-------------- ---------------
+gen_fsm:start
+gen_fsm:start_link -----> Module:init/1
+
+gen_fsm:stop -----> Module:terminate/3
+
+gen_fsm:send_event -----> Module:StateName/2
+
+gen_fsm:send_all_state_event -----> Module:handle_event/3
+
+gen_fsm:sync_send_event -----> Module:StateName/3
+
+gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
+
+- -----> Module:handle_info/3
+
+- -----> Module:terminate/3
+
+- -----> Module:code_change/4</pre>
+
+ If a callback function fails or returns a bad value, the <c>gen_fsm</c>
+ process terminates.
+
+ A <c>gen_fsm</c> process handles system messages as described in
+ <seeerl marker="sys"><c>sys(3)</c></seeerl>. The <c>sys</c> module
+ can be used for debugging a <c>gen_fsm</c> process.
+
+ Notice that a <c>gen_fsm</c> process does not trap exit signals
+ automatically, this must be explicitly initiated in the callback
+ module.
+
+ Unless otherwise stated, all functions in this module fail if
+ the specified <c>gen_fsm</c> process does not exist or if bad arguments
+ are specified.
+
+ The <c>gen_fsm</c> process can go into hibernation
+ (see <seemfa marker="erts:erlang#hibernate/3">
+ <c>erlang:hibernate/3</c></seemfa>) if a callback function
+ specifies <c>'hibernate'</c> instead of a time-out value. This
+ can be useful if the server is expected to be idle for a long
+ time. However, use this feature with care, as hibernation
+ implies at least two garbage collections (when hibernating and
+ shortly after waking up) and is not something you want to do
+ between each call to a busy state machine.
 </description>
+
+ <funcs>
+ <func>
+ <name>cancel_timer(Ref) -> RemainingTime | false</name>
+ <fsummary>Cancel an internal timer in a generic FSM.</fsummary>
+ <type>
+ <v>Ref = reference()</v>
+ <v>RemainingTime = integer()</v>
+ </type>
+ <desc>
+ Cancels an internal timer referred by <c>Ref</c> in the
+ <c>gen_fsm</c> process that calls this function.
+ <c>Ref</c> is a reference returned from
+ <seemfa marker="#send_event_after/2">
+ <c>send_event_after/2</c></seemfa> or
+ <seemfa marker="#start_timer/2"><c>start_timer/2</c></seemfa>.
+ If the timer has already timed out, but the event not yet
+ been delivered, it is cancelled as if it had not
+ timed out, so there is no false timer event after
+ returning from this function.
+ Returns the remaining time in milliseconds until the timer would
+ have expired if <c>Ref</c> referred to an active timer, otherwise
+ <c>false</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>enter_loop(Module, Options, StateName, StateData)</name>
+ <name>enter_loop(Module, Options, StateName, StateData, FsmName)</name>
+ <name>enter_loop(Module, Options, StateName, StateData, Timeout)</name>
+ <name>enter_loop(Module, Options, StateName, StateData, FsmName, Timeout)</name>
+ <fsummary>Enter the <c>gen_fsm</c> receive loop.</fsummary>
+ <type>
+ <v>Module = atom()</v>
+ <v>Options = [Option]</v>
+ <v>&nbsp;Option = {debug,Dbgs}</v>
+ <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
+ <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
+ <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
+ <v>StateName = atom()</v>
+ <v>StateData = term()</v>
+ <v>FsmName = {local,Name} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
+ <v>&nbsp;Name = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Timeout = int() | infinity</v>
+ </type>
+ <desc>
+ Makes an existing process into a <c>gen_fsm</c> process.
+ Does not return,
+ instead the calling process enters the <c>gen_fsm</c> receive
+ loop and becomes a <c>gen_fsm</c> process. The process must
+ have been started using one of the start functions in
+ <seeerl marker="proc_lib"><c>proc_lib(3)</c></seeerl>. The user is
+ responsible for any initialization of the process, including
+ registering a name for it.
+ This function is useful when a more complex initialization
+ procedure is needed than the <c>gen_fsm</c> behavior provides.
+ <c>Module</c>, <c>Options</c>, and <c>FsmName</c> have
+ the same meanings as when calling
+ <seemfa marker="#start_link/3"><c>start[_link]/3,4</c></seemfa>.
+ However, if <c>FsmName</c> is specified, the process must have
+ been registered accordingly before this function is
+ called.
+ <c>StateName</c>, <c>StateData</c>, and <c>Timeout</c> have
+ the same meanings as in the return value of
+ <seemfa marker="#Module:init/1"><c>Module:init/1</c></seemfa>.
+ The callback module <c>Module</c> does not need to
+ export an <c>init/1</c> function.
+ The function fails if the calling process was not started by a
+ <c>proc_lib</c> start function, or if it is not registered
+ according to <c>FsmName</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>reply(Caller, Reply) -> Result</name>
+ <fsummary>Send a reply to a caller.</fsummary>
+ <type>
+ <v>Caller - see below</v>
+ <v>Reply = term()</v>
+ <v>Result = term()</v>
+ </type>
+ <desc>
+ This function can be used by a <c>gen_fsm</c> process to
+ explicitly send a reply to a client process that called
+ <seemfa marker="#sync_send_event/2">
+ <c>sync_send_event/2,3</c></seemfa> or
+ <seemfa marker="#sync_send_all_state_event/2">
+ <c>sync_send_all_state_event/2,3</c></seemfa>
+ when the reply cannot be defined in the return value of
+ <seemfa marker="#Module:StateName/3">
+ <c>Module:StateName/3</c></seemfa> or
+ <seemfa marker="#Module:handle_sync_event/4">
+ <c>Module:handle_sync_event/4</c></seemfa>.
+ <c>Caller</c> must be the <c>From</c> argument provided to
+ the callback function. <c>Reply</c> is any term
+ given back to the client as the return value of
+ <c>sync_send_event/2,3</c> or
+ <c>sync_send_all_state_event/2,3</c>.
+ Return value <c>Result</c> is not further defined, and
+ is always to be ignored.
+ </desc>
+ </func>
+
+ <func>
+ <name>send_all_state_event(FsmRef, Event) -> ok</name>
+ <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
+ <type>
+ <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
+ <v>&nbsp;Name = Node = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Event = term()</v>
+ </type>
+ <desc>
+ Sends an event asynchronously to the <c>FsmRef</c> of the
+ <c>gen_fsm</c> process and returns <c>ok</c> immediately.
+ The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:handle_event/3">
+ <c>Module:handle_event/3</c></seemfa> to handle the event.
+ For a description of the arguments, see
+ <seemfa marker="#send_event/2"><c>send_event/2</c></seemfa>.
+ The difference between <c>send_event/2</c> and
+ <c>send_all_state_event/2</c> is which callback function is
+ used to handle the event. This function is useful when
+ sending events that are handled the same way in every state,
+ as only one <c>handle_event</c> clause is needed to handle
+ the event instead of one clause in each state name function.
+ </desc>
+ </func>
+
+ <func>
+ <name>send_event(FsmRef, Event) -> ok</name>
+ <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
+ <type>
+ <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
+ <v>&nbsp;Name = Node = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Event = term()</v>
+ </type>
+ <desc>
+ Sends an event asynchronously to the <c>FsmRef</c> of the
+ <c>gen_fsm</c> process 
+ and returns <c>ok</c> immediately. The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa> to handle the event, where
+ <c>StateName</c> is the name of the current state of
+ the <c>gen_fsm</c> process.
+ <c>FsmRef</c> can be any of the following:
+ <list type="bulleted">
+ <item>The pid</item>
+ <item><c>Name</c>, if the <c>gen_fsm</c> process is locally
+ registered</item>
+ <item><c>{Name,Node}</c>, if the <c>gen_fsm</c> process is locally
+ registered at another node</item>
+ <item><c>{global,GlobalName}</c>, if the <c>gen_fsm</c> process is
+ globally registered</item>
+ <item><c>{via,Module,ViaName}</c>, if the <c>gen_fsm</c> process is
+ registered through an alternative process registry</item>
+ </list>
+ <c>Event</c> is any term that is passed as one of
+ the arguments to <c>Module:StateName/2</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>send_event_after(Time, Event) -> Ref</name>
+ <fsummary>Send a delayed event internally in a generic FSM.</fsummary>
+ <type>
+ <v>Time = integer()</v>
+ <v>Event = term()</v>
+ <v>Ref = reference()</v>
+ </type>
+ <desc>
+ Sends a delayed event internally in the <c>gen_fsm</c> process
+ that calls this function after <c>Time</c> milliseconds.
+ Returns immediately a
+ reference that can be used to cancel the delayed send using
+ <seemfa marker="#cancel_timer/1"><c>cancel_timer/1</c></seemfa>.
+ The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa> to handle
+ the event, where <c>StateName</c> is the name of the current
+ state of the <c>gen_fsm</c> process at the time the delayed event is
+ delivered.
+ <c>Event</c> is any term that is passed as one of
+ the arguments to <c>Module:StateName/2</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>start(Module, Args, Options) -> Result</name>
+ <name>start(FsmName, Module, Args, Options) -> Result</name>
+ <fsummary>Create a standalone <c>gen_fsm</c> process.</fsummary>
+ <type>
+ <v>FsmName = {local,Name} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
+ <v>&nbsp;Name = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Module = atom()</v>
+ <v>Args = term()</v>
+ <v>Options = [Option]</v>
+ <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+ <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
+ <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
+ <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
+ <v>&nbsp;&nbsp;SOpts = [term()]</v>
+ <v>Result = {ok,Pid} | ignore | {error,Error}</v>
+ <v>&nbsp;Pid = pid()</v>
+ <v>&nbsp;Error = {already_started,Pid} | term()</v>
+ </type>
+ <desc>
+ Creates a standalone <c>gen_fsm</c> process, that is, a process that
+ is not part of a supervision tree and thus has no supervisor.
+ For a description of arguments and return values, see
+ <seemfa marker="#start_link/3"><c>start_link/3,4</c></seemfa>.
+ </desc>
+ </func>
+
+ <func>
+ <name>start_link(Module, Args, Options) -> Result</name>
+ <name>start_link(FsmName, Module, Args, Options) -> Result</name>
+ <fsummary>Create a <c>gen_fsm</c> process in a supervision tree.
+ </fsummary>
+ <type>
+ <v>FsmName = {local,Name} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
+ <v>&nbsp;Name = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Module = atom()</v>
+ <v>Args = term()</v>
+ <v>Options = [Option]</v>
+ <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+ <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
+ <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
+ <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
+ <v>&nbsp;&nbsp;SOpts = [SOpt]</v>
+ <v>&nbsp;&nbsp;&nbsp;SOpt - see erlang:spawn_opt/2,3,4,5</v>
+ <v>Result = {ok,Pid} | ignore | {error,Error}</v>
+ <v>&nbsp;Pid = pid()</v>
+ <v>&nbsp;Error = {already_started,Pid} | term()</v>
+ </type>
+ <desc>
+ Creates a <c>gen_fsm</c> process as part of a supervision tree.
+ The function is to be called, directly or indirectly, by
+ the supervisor. For example, it ensures that
+ the <c>gen_fsm</c> process is linked to the supervisor.
+ The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:init/1"><c>Module:init/1</c></seemfa> to
+ initialize. To ensure a synchronized startup procedure,
+ <c>start_link/3,4</c> does not return until
+ <c>Module:init/1</c> has returned.
+ <list type="bulleted">
+ <item>
+ If <c>FsmName={local,Name}</c>, the <c>gen_fsm</c> process is
+ registered locally as <c>Name</c> using <c>register/2</c>.
+ </item>
+ <item>
+ If <c>FsmName={global,GlobalName}</c>, the <c>gen_fsm</c> process
+ is registered globally as <c>GlobalName</c> using
+ <seemfa marker="kernel:global#register_name/2">
+ <c>global:register_name/2</c></seemfa>.
+ </item>
+ <item>
+ If <c>FsmName={via,Module,ViaName}</c>, the <c>gen_fsm</c>
+ process registers with the registry represented by <c>Module</c>.
+ The <c>Module</c> callback is to export the functions
+ <c>register_name/2</c>, <c>unregister_name/1</c>,
+ <c>whereis_name/1</c>, and <c>send/2</c>, which are to behave
+ like the corresponding functions in
+ <seeerl marker="kernel:global"><c>global</c></seeerl>.
+ Thus, <c>{via,global,GlobalName}</c> is a valid reference.
+ </item>
+ </list>
+ If no name is provided, the <c>gen_fsm</c> process is not
+ registered.
+ <c>Module</c> is the name of the callback module.
+ <c>Args</c> is any term that is passed as
+ the argument to <c>Module:init/1</c>.
+ If option <c>{timeout,Time}</c> is present, the <c>gen_fsm</c>
+ process is allowed to spend <c>Time</c> milliseconds initializing
+ or it terminates and the start function returns
+ <c>{error,timeout}</c>.
+ If option <c>{debug,Dbgs}</c> is present, the corresponding
+ <c>sys</c> function is called for each item in <c>Dbgs</c>; see
+ <seeerl marker="sys"><c>sys(3)</c></seeerl>.
+ If option <c>{spawn_opt,SOpts}</c> is present, <c>SOpts</c> is
+ passed as option list to the <c>spawn_opt</c> BIF that is used to
+ spawn the <c>gen_fsm</c> process; see
+ <seemfa marker="erts:erlang#spawn_opt/2">
+ <c>spawn_opt/2</c></seemfa>.
+ <note>
+ Using spawn option <c>monitor</c> is not
+ allowed, it causes the function to fail with reason
+ <c>badarg</c>.
+ </note>
+ If the <c>gen_fsm</c> process is successfully created and
+ initialized, the function returns <c>{ok,Pid}</c>, where <c>Pid</c>
+ is the pid of the <c>gen_fsm</c> process. If a process with the
+ specified <c>FsmName</c> exists already, the function returns
+ <c>{error,{already_started,Pid}}</c>, where <c>Pid</c> is
+ the pid of that process.
+ If <c>Module:init/1</c> fails with <c>Reason</c>,
+ the function returns <c>{error,Reason}</c>. If
+ <c>Module:init/1</c> returns <c>{stop,Reason}</c> or
+ <c>ignore</c>, the process is terminated and the function
+ returns <c>{error,Reason}</c> or <c>ignore</c>, respectively.
+ </desc>
+ </func>
+
+ <func>
+ <name>start_timer(Time, Msg) -> Ref</name>
+ <fsummary>Send a time-out event internally in a generic FSM.</fsummary>
+ <type>
+ <v>Time = integer()</v>
+ <v>Msg = term()</v>
+ <v>Ref = reference()</v>
+ </type>
+ <desc>
+ Sends a time-out event internally in the <c>gen_fsm</c>
+ process that calls this function after <c>Time</c> milliseconds.
+ Returns immediately a
+ reference that can be used to cancel the timer using
+ <seemfa marker="#cancel_timer/1"><c>cancel_timer/1</c></seemfa>.
+ The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa> to handle
+ the event, where <c>StateName</c> is the name of the current
+ state of the <c>gen_fsm</c> process at the time the time-out
+ message is delivered.
+ <c>Msg</c> is any term that is passed in the
+ time-out message, <c>{timeout, Ref, Msg}</c>, as one of
+ the arguments to <c>Module:StateName/2</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>stop(FsmRef) -> ok</name>
+ <name>stop(FsmRef, Reason, Timeout) -> ok</name>
+ <fsummary>Synchronously stop a generic FSM.</fsummary>
+ <type>
+ <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
+ <v>&nbsp;Node = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Reason = term()</v>
+ <v>Timeout = int()>0 | infinity</v>
+ </type>
+ <desc>
+ Orders a generic finite state machine to exit with the specified
+ <c>Reason</c> and waits for it to terminate. The <c>gen_fsm</c>
+ process calls <seemfa marker="#Module:terminate/3">
+ <c>Module:terminate/3</c></seemfa> before exiting.
+ The function returns <c>ok</c> if the generic finite state machine
+ terminates with the expected reason. Any other reason than
+ <c>normal</c>, <c>shutdown</c>, or <c>{shutdown,Term}</c> causes an
+ error report to be issued using
+ <seemfa marker="kernel:error_logger#format/2">
+ <c>error_logger:format/2</c></seemfa>.
+ The default <c>Reason</c> is <c>normal</c>.
+ <c>Timeout</c> is an integer greater than zero that
+ specifies how many milliseconds to wait for the generic FSM
+ to terminate, or the atom <c>infinity</c> to wait
+ indefinitely. The default value is <c>infinity</c>. If the
+ generic finite state machine has not terminated within the specified
+ time, a <c>timeout</c> exception is raised.
+ If the process does not exist, a <c>noproc</c> exception
+ is raised.
+ </desc>
+ </func>
+
+ <func>
+ <name>sync_send_all_state_event(FsmRef, Event) -> Reply</name>
+ <name>sync_send_all_state_event(FsmRef, Event, Timeout) -> Reply</name>
+ <fsummary>Send an event synchronously to a generic FSM.</fsummary>
+ <type>
+ <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
+ <v>&nbsp;Name = Node = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Event = term()</v>
+ <v>Timeout = int()>0 | infinity</v>
+ <v>Reply = term()</v>
+ </type>
+ <desc>
+ Sends an event to the <c>FsmRef</c> of the <c>gen_fsm</c>
+ process and waits until a reply arrives or a time-out occurs.
+ The <c>gen_fsm</c> process calls
+ <seemfa marker="#Module:handle_sync_event/4">
+ <c>Module:handle_sync_event/4</c></seemfa> to handle the event.
+ For a description of <c>FsmRef</c> and <c>Event</c>, see
+ <seemfa marker="#send_event/2">send_event/2</seemfa>.
+ For a description of <c>Timeout</c> and <c>Reply</c>, see
+ <seemfa marker="#sync_send_event/3">
+ <c>sync_send_event/3</c></seemfa>.
+ For a discussion about the difference between
+ <c>sync_send_event</c> and <c>sync_send_all_state_event</c>, see
+ <seemfa marker="#send_all_state_event/2">
+ <c>send_all_state_event/2</c></seemfa>.
+ </desc>
+ </func>
+
+ <func>
+ <name>sync_send_event(FsmRef, Event) -> Reply</name>
+ <name>sync_send_event(FsmRef, Event, Timeout) -> Reply</name>
+ <fsummary>Send an event synchronously to a generic FSM.</fsummary>
+ <type>
+ <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
+ <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
+ <v>&nbsp;Name = Node = atom()</v>
+ <v>&nbsp;GlobalName = ViaName = term()</v>
+ <v>Event = term()</v>
+ <v>Timeout = int()>0 | infinity</v>
+ <v>Reply = term()</v>
+ </type>
+ <desc>
+ Sends an event to the <c>FsmRef</c> of the <c>gen_fsm</c>
+ process and waits until a reply arrives or a time-out occurs.
+ <c>The gen_fsm</c> process calls
+ <seemfa marker="#Module:StateName/3">
+ <c>Module:StateName/3</c></seemfa> to handle the event, where
+ <c>StateName</c> is the name of the current state of
+ the <c>gen_fsm</c> process.
+ For a description of <c>FsmRef</c> and <c>Event</c>, see
+ <seemfa marker="#send_event/2"><c>send_event/2</c></seemfa>.
+ <c>Timeout</c> is an integer greater than zero that
+ specifies how many milliseconds to wait for a reply, or
+ the atom <c>infinity</c> to wait indefinitely. Defaults
+ to 5000. If no reply is received within the specified time,
+ the function call fails.
+ Return value <c>Reply</c> is defined in the return value
+ of <c>Module:StateName/3</c>.
+	<note>
+ The ancient behavior of sometimes consuming the server
+ exit message if the server died during the call while
+ linked to the client was removed in Erlang 5.6/OTP R12B.
+	</note>
+ </desc>
+ </func>
+ </funcs>
+
+ <section>
+ <title>Callback Functions</title>
+ The following functions are to be exported from a <c>gen_fsm</c>
+ callback module.
+
+ state name denotes a state of the state machine.
+
+ state data denotes the internal state of the Erlang process
+ that implements the state machine.
+ </section>
+
+ <funcs>
+ <func>
+ <name>Module:code_change(OldVsn, StateName, StateData, Extra) -> {ok, NextStateName, NewStateData}</name>
+ <fsummary>Update the internal state data during upgrade/downgrade.
+ </fsummary>
+ <type>
+ <v>OldVsn = Vsn | {down, Vsn}</v>
+ <v>&nbsp;&nbsp;Vsn = term()</v>
+ <v>StateName = NextStateName = atom()</v>
+ <v>StateData = NewStateData = term()</v>
+ <v>Extra = term()</v>
+ </type>
+ <desc>
+ This function is called by a <c>gen_fsm</c> process when it is to
+ update its internal state data during a release upgrade/downgrade,
+ that is, when instruction <c>{update,Module,Change,...}</c>,
+ where <c>Change={advanced,Extra}</c>, is given in
+ the <c>appup</c> file; see section
+ <seeguide marker="doc/design_principles:release_handling#instr">
+ Release Handling Instructions</seeguide> in OTP Design Principles.
+ For an upgrade, <c>OldVsn</c> is <c>Vsn</c>, and for a downgrade,
+ <c>OldVsn</c> is <c>{down,Vsn}</c>. <c>Vsn</c> is defined by the
+ <c>vsn</c> attribute(s) of the old version of the callback module
+ <c>Module</c>. If no such attribute is defined, the version is
+ the checksum of the Beam file.
+ <c>StateName</c> is the current state name and <c>StateData</c> the
+ internal state data of the <c>gen_fsm</c> process.
+ <c>Extra</c> is passed "as is" from the <c>{advanced,Extra}</c>
+ part of the update instruction.
+ The function is to return the new current state name and
+ updated internal data.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:format_status(Opt, [PDict, StateData]) -> Status</name>
+ <fsummary>Optional function for providing a term describing the
+ current <c>gen_fsm</c> process status.</fsummary>
+ <type>
+ <v>Opt = normal | terminate</v>
+ <v>PDict = [{Key, Value}]</v>
+ <v>StateData = term()</v>
+ <v>Status = term()</v>
+ </type>
+ <desc>
+ <note>
+ This callback is optional, so callback modules need not
+ export it. The <c>gen_fsm</c> module provides a default
+ implementation of this function that returns the callback
+ module state data.
+ </note>
+ This function is called by a <c>gen_fsm</c> process in the
+ following situations:
+ <list type="bulleted">
+ <item>One of <seemfa marker="sys#get_status/1">
+ <c>sys:get_status/1,2</c></seemfa>
+ is invoked to get the <c>gen_fsm</c> status. <c>Opt</c> is set to
+ the atom <c>normal</c> for this case.</item>
+ <item>The <c>gen_fsm</c> process terminates abnormally and logs an
+ error. <c>Opt</c> is set to the atom <c>terminate</c> for
+ this case.</item>
+ </list>
+ This function is useful for changing the form and
+ appearance of the <c>gen_fsm</c> status for these cases. A callback
+ module wishing to change the <c>sys:get_status/1,2</c>
+ return value as well as how its status appears in
+ termination error logs, exports an instance
+ of <c>format_status/2</c> that returns a term describing the
+ current status of the <c>gen_fsm</c> process.
+ <c>PDict</c> is the current value of the process dictionary of the
+ <c>gen_fsm</c> process.
+ <c>StateData</c> is the internal state data of the
+ <c>gen_fsm</c> process.
+ The function is to return <c>Status</c>, a term that
+ change the details of the current state and status of
+ the <c>gen_fsm</c> process. There are no restrictions on the
+ form <c>Status</c> can take, but for
+ the <c>sys:get_status/1,2</c> case (when <c>Opt</c>
+ is <c>normal</c>), the recommended form for
+ the <c>Status</c> value is <c>[{data, [{"StateData",
+ Term}]}]</c>, where <c>Term</c> provides relevant details of
+ the <c>gen_fsm</c> state data. Following this recommendation is not
+ required, but it makes the callback module status
+ consistent with the rest of the <c>sys:get_status/1,2</c>
+ return value.
+ One use for this function is to return compact alternative
+ state data representations to avoid that large state terms
+ are printed in log files.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:handle_event(Event, StateName, StateData) -> Result</name>
+ <fsummary>Handle an asynchronous event.</fsummary>
+ <type>
+ <v>Event = term()</v>
+ <v>StateName = atom()</v>
+ <v>StateData = term()</v>
+ <v>Result = {next_state,NextStateName,NewStateData}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
+ <v>&nbsp;NextStateName = atom()</v>
+ <v>&nbsp;NewStateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = term()</v>
+ </type>
+ <desc>
+ Whenever a <c>gen_fsm</c> process receives an event sent using
+ <seemfa marker="#send_all_state_event/2">
+ <c>send_all_state_event/2</c></seemfa>,
+ this function is called to handle the event.
+ <c>StateName</c> is the current state name of the <c>gen_fsm</c>
+ process.
+ For a description of the other arguments and possible return values,
+ see <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa>.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:handle_info(Info, StateName, StateData) -> Result</name>
+ <fsummary>Handle an incoming message.</fsummary>
+ <type>
+ <v>Info = term()</v>
+ <v>StateName = atom()</v>
+ <v>StateData = term()</v>
+ <v>Result = {next_state,NextStateName,NewStateData}</v> 
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
+ <v>&nbsp;NextStateName = atom()</v>
+ <v>&nbsp;NewStateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = normal | term()</v>
+ </type>
+ <desc>
+ This function is called by a <c>gen_fsm</c> process when it receives
+ any other message than a synchronous or asynchronous event (or a
+ system message).
+ <c>Info</c> is the received message.
+ For a description of the other arguments and possible return values,
+ see <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa>.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:handle_sync_event(Event, From, StateName, StateData) -> Result</name>
+ <fsummary>Handle a synchronous event.</fsummary>
+ <type>
+ <v>Event = term()</v>
+ <v>From = {pid(),Tag}</v>
+ <v>StateName = atom()</v>
+ <v>StateData = term()</v>
+ <v>Result = {reply,Reply,NextStateName,NewStateData}</v>
+ <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,Timeout}</v> 
+ <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData}</v> 
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v> 
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason,Reply,NewStateData} | {stop,Reason,NewStateData}</v>
+ <v>&nbsp;Reply = term()</v>
+ <v>&nbsp;NextStateName = atom()</v>
+ <v>&nbsp;NewStateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = term()</v>
+ </type>
+ <desc>
+ Whenever a <c>gen_fsm</c> process receives an event sent using
+ <seemfa marker="#sync_send_all_state_event/2">
+ <c>sync_send_all_state_event/2,3</c></seemfa>,
+ this function is called to handle the event.
+ <c>StateName</c> is the current state name of the <c>gen_fsm</c>
+ process.
+ For a description of the other arguments and possible return values,
+ see <seemfa marker="#Module:StateName/3">
+ <c>Module:StateName/3</c></seemfa>.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:init(Args) -> Result</name>
+ <fsummary>Initialize process and internal state name and state data.
+ </fsummary>
+ <type>
+ <v>Args = term()</v>
+ <v>Result = {ok,StateName,StateData} | {ok,StateName,StateData,Timeout}</v>
+ <v>&nbsp;&nbsp;| {ok,StateName,StateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason} | ignore</v>
+ <v>&nbsp;StateName = atom()</v>
+ <v>&nbsp;StateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = term()</v>
+ </type>
+ <desc>
+ <marker id="Moduleinit"></marker>
+ Whenever a <c>gen_fsm</c> process is started using
+ <seemfa marker="#start/3"><c>start/3,4</c></seemfa> or
+ <seemfa marker="#start_link/3"><c>start_link/3,4</c></seemfa>,
+ this function is called by the new process to initialize.
+ <c>Args</c> is the <c>Args</c> argument provided to the start
+ function.
+ If initialization is successful, the function is to return
+ <c>{ok,StateName,StateData}</c>,
+ <c>{ok,StateName,StateData,Timeout}</c>, or
+ <c>{ok,StateName,StateData,hibernate}</c>, where <c>StateName</c>
+ is the initial state name and <c>StateData</c> the initial
+ state data of the <c>gen_fsm</c> process.
+ If an integer time-out value is provided, a time-out occurs
+ unless an event or a message is received within <c>Timeout</c>
+ milliseconds. A time-out is represented by the atom
+ <c>timeout</c> and is to be handled by the
+ <seemfa marker="#Module:StateName/2">
+ <c>Module:StateName/2</c></seemfa> callback functions. The atom
+ <c>infinity</c> can be used to wait indefinitely, this is
+ the default value.
+ If <c>hibernate</c> is specified instead of a time-out value, the
+ process goes into hibernation when waiting for the next message
+ to arrive (by calling <seemfa marker="proc_lib#hibernate/3">
+ <c>proc_lib:hibernate/3</c></seemfa>).
+ If the initialization fails, the function returns
+ <c>{stop,Reason}</c>, where <c>Reason</c> is any term,
+ or <c>ignore</c>.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:StateName(Event, StateData) -> Result</name>
+ <fsummary>Handle an asynchronous event.</fsummary>
+ <type>
+ <v>Event = timeout | term()</v>
+ <v>StateData = term()</v>
+ <v>Result = {next_state,NextStateName,NewStateData} </v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
+ <v>&nbsp;NextStateName = atom()</v>
+ <v>&nbsp;NewStateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = term()</v>
+ </type>
+ <desc>
+ There is to be one instance of this function for each
+ possible state name. Whenever a <c>gen_fsm</c> process receives
+ an event sent using
+ <seemfa marker="#send_event/2"><c>send_event/2</c></seemfa>,
+ the instance of this function with the same name as
+ the current state name <c>StateName</c> is called to handle
+ the event. It is also called if a time-out occurs.
+ <c>Event</c> is either the atom <c>timeout</c>, if a time-out
+ has occurred, or the <c>Event</c> argument provided to
+ <c>send_event/2</c>.
+ <c>StateData</c> is the state data of the <c>gen_fsm</c> process.
+ If the function returns
+ <c>{next_state,NextStateName,NewStateData}</c>, 
+ <c>{next_state,NextStateName,NewStateData,Timeout}</c>, or
+ <c>{next_state,NextStateName,NewStateData,hibernate}</c>, the
+ <c>gen_fsm</c> process continues executing with the current state
+ name set to <c>NextStateName</c> and with the possibly
+ updated state data <c>NewStateData</c>. For a description of
+ <c>Timeout</c> and <c>hibernate</c>, see
+ <seemfa marker="#Module:init/1"><c>Module:init/1</c></seemfa>.
+ If the function returns <c>{stop,Reason,NewStateData}</c>,
+ the <c>gen_fsm</c> process calls
+ <c>Module:terminate(Reason,StateName,NewStateData)</c> and
+ terminates.
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:StateName(Event, From, StateData) -> Result</name>
+ <fsummary>Handle a synchronous event.</fsummary>
+ <type>
+ <v>Event = term()</v>
+ <v>From = {pid(),Tag}</v>
+ <v>StateData = term()</v>
+ <v>Result = {reply,Reply,NextStateName,NewStateData}</v> 
+ <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,Timeout}</v> 
+ <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData}</v> 
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v> 
+ <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
+ <v>&nbsp;&nbsp;| {stop,Reason,Reply,NewStateData} | {stop,Reason,NewStateData}</v>
+ <v>&nbsp;Reply = term()</v>
+ <v>&nbsp;NextStateName = atom()</v>
+ <v>&nbsp;NewStateData = term()</v>
+ <v>&nbsp;Timeout = int()>0 | infinity</v>
+ <v>&nbsp;Reason = normal | term()</v>
+ </type>
+ <desc>
+ There is to be one instance of this function for each
+ possible state name. Whenever a <c>gen_fsm</c> process receives an
+ event sent using <seemfa marker="#sync_send_event/2">
+ <c>sync_send_event/2,3</c></seemfa>,
+ the instance of this function with the same name as
+ the current state name <c>StateName</c> is called to handle
+ the event.
+ <c>Event</c> is the <c>Event</c> argument provided to
+ <c>sync_send_event/2,3</c>.
+ <c>From</c> is a tuple <c>{Pid,Tag}</c> where <c>Pid</c> is
+ the pid of the process that called <c>sync_send_event/2,3</c>
+ and <c>Tag</c> is a unique tag.
+ <c>StateData</c> is the state data of the <c>gen_fsm</c> process.
+ <list type="bulleted">
+ <item>
+ If <c>{reply,Reply,NextStateName,NewStateData}</c>, 
+ <c>{reply,Reply,NextStateName,NewStateData,Timeout}</c>, or 
+ <c>{reply,Reply,NextStateName,NewStateData,hibernate}</c> is
+ returned, <c>Reply</c> is given back to <c>From</c> as the return
+ value of <c>sync_send_event/2,3</c>. The <c>gen_fsm</c> process
+ then continues executing with the current state name set to
+ <c>NextStateName</c> and with the possibly updated state data
+ <c>NewStateData</c>. For a description of <c>Timeout</c> and
+ <c>hibernate</c>, see
+ <seemfa marker="#Module:init/1">
+ <c>Module:init/1</c></seemfa>.
+ </item>
+ <item>
+ If <c>{next_state,NextStateName,NewStateData}</c>, 
+ <c>{next_state,NextStateName,NewStateData,Timeout}</c>, or
+ <c>{next_state,NextStateName,NewStateData,hibernate}</c> is
+ returned, the <c>gen_fsm</c> process continues executing in
+ <c>NextStateName</c> with <c>NewStateData</c>.
+ Any reply to <c>From</c> must be specified explicitly using
+ <seemfa marker="#reply/2"><c>reply/2</c></seemfa>.
+ </item>
+ <item>
+ If the function returns
+ <c>{stop,Reason,Reply,NewStateData}</c>, <c>Reply</c> is
+ given back to <c>From</c>. If the function returns
+ <c>{stop,Reason,NewStateData}</c>, any reply to <c>From</c>
+ must be specified explicitly using <c>reply/2</c>.
+ The <c>gen_fsm</c> process then calls
+ <c>Module:terminate(Reason,StateName,NewStateData)</c> and
+ terminates.
+ </item>
+ </list>
+ </desc>
+ </func>
+
+ <func>
+ <name>Module:terminate(Reason, StateName, StateData)</name>
+ <fsummary>Clean up before termination.</fsummary>
+ <type>
+ <v>Reason = normal | shutdown | {shutdown,term()} | term()</v>
+ <v>StateName = atom()</v>
+ <v>StateData = term()</v>
+ </type>
+ <desc>
+ This function is called by a <c>gen_fsm</c> process when it is about
+ to terminate. It is to be the opposite of
+ <seemfa marker="#Module:init/1"><c>Module:init/1</c></seemfa>
+ and do any necessary cleaning up. When it returns, the <c>gen_fsm</c>
+ process terminates with <c>Reason</c>. The return value is ignored.
+ 
+ <c>Reason</c> is a term denoting the stop reason,
+ <c>StateName</c> is the current state name, and
+ <c>StateData</c> is the state data of the <c>gen_fsm</c> process.
+ <c>Reason</c> depends on why the <c>gen_fsm</c> process is
+ terminating. If
+ it is because another callback function has returned a stop
+ tuple <c>{stop,..}</c>, <c>Reason</c> has the value
+ specified in that tuple. If it is because of a failure,
+ <c>Reason</c> is the error reason.
+ If the <c>gen_fsm</c> process is part of a supervision tree and is
+ ordered by its supervisor to terminate, this function is called
+ with <c>Reason=shutdown</c> if the following conditions apply:
+ <list type="bulleted">
+ <item>
+ The <c>gen_fsm</c> process has been set to trap exit signals.
+ </item>
+ <item>
+ The shutdown strategy as defined in the child specification of
+ the supervisor is an integer time-out value, not
+ <c>brutal_kill</c>.
+ </item>
+ </list>
+ Even if the <c>gen_fsm</c> process is not part of a
+ supervision tree,
+ this function is called if it receives an <c>'EXIT'</c>
+ message from its parent. <c>Reason</c> is the same as in
+ the <c>'EXIT'</c> message.
+ Otherwise, the <c>gen_fsm</c> process terminates immediately.
+ Notice that for any other reason than <c>normal</c>,
+ <c>shutdown</c>, or <c>{shutdown,Term}</c> the <c>gen_fsm</c> process
+ is assumed to terminate because of an error and an error report is
+ issued using <seemfa marker="kernel:error_logger#format/2">
+ <c>error_logger:format/2</c></seemfa>.
+ </desc>
+ </func>
+ </funcs>
+
 <section>
 <marker id="Migration to gen_statem"/>
 <title>Migration to gen_statem</title>
@@ -201,4 +1114,14 @@ do_unlock() ->
 io:format("Unlock~n", []).
 </code>
 </section>
+
+ <section>
+ <title>See Also</title>
+ <seeerl marker="gen_event"><c>gen_event(3)</c></seeerl>,
+ <seeerl marker="gen_server"><c>gen_server(3)</c></seeerl>,
+ <seeerl marker="gen_statem"><c>gen_statem(3)</c></seeerl>,
+ <seeerl marker="proc_lib"><c>proc_lib(3)</c></seeerl>,
+ <seeerl marker="supervisor"><c>supervisor(3)</c></seeerl>,
+ <seeerl marker="sys"><c>sys(3)</c></seeerl>
+ </section>
 </erlref>
diff -Ndurp otp_src_23.3.4.20/lib/stdlib/doc/src/Makefile otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm/lib/stdlib/doc/src/Makefile
--- otp_src_23.3.4.20/lib/stdlib/doc/src/Makefile	2024-03-14 09:08:00.000000000 +0200
+++ otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm/lib/stdlib/doc/src/Makefile	2024-09-26 01:37:18.091048836 +0300
@@ -115,6 +115,6 @@ $(SPECDIR)/specs_erl_id_trans.xml:
 	$(gen_verbose)escript $(SPECS_EXTRACTOR) $(SPECS_FLAGS) \
 		-o$(dir $@) -module erl_id_trans
 
-NO_CHUNKS = erl_id_trans.xml
+NO_CHUNKS = erl_id_trans.xml gen_fsm.xml
 
 include $(ERL_TOP)/make/doc.mk

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File otp_src_23.3.4.20-lib-stdlib-doc-gen_fsm.patch of Package erlang (Revision 58ddfd9fcf4c281c82656d8c2d2a71df)

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