Valgrind checks all memory operations in an application, like read,
write, malloc, new, free, and delete. Valgrind can find uses of
uninitialized memory, access to already freed memory, overflows,
illegal stack operations, memory leaks, and any illegal
new/malloc/free/delete commands. Another program in the package is
"cachegrind," a profiler based on the valgrind engine.

To use valgrind you should compile your application with "-g -O0"
compiler options. Afterwards you can use it with:

valgrind --tool=memcheck --sloppy-malloc=yes --leak-check=yes
--db-attach=yes my_application, for example.

More valgrind options can be listed via "valgrind --help". There is
also complete documentation in the /usr/share/doc/packages/valgrind/
directory. A debugged application runs slower and needs much more
memory, but is usually still usable. Valgrind is still in development,
but it has been successfully used to optimize several KDE applications.