The
atexit()
function registers the given function to be
called at normal process termination, either via
exit(3)
or via return from the program's main().
Functions so registered are called in
the reverse order of their registration; no arguments are passed.
POSIX.1-2001 requires that an implementation allow at least
ATEXIT_MAX
(32) such functions to be registered.
The actual limit supported by an implementation can be obtained using
sysconf(3).
When a child process is created via
fork(2),
it inherits copies of its parent's registrations.
Upon a successful call to one of the
exec(3)
functions,
all registrations are removed.
RETURN VALUE
The
atexit()
function returns the value 0 if successful; otherwise
it returns a non-zero value.
CONFORMING TO
SVr4, 4.3BSD, C89, C99, POSIX.1-2001.
NOTES
Functions registered using
atexit()
(and
on_exit(3))
are not called if a process terminates abnormally because
of the delivery of a signal.
Linux Notes
Since glibc 2.2.3,
atexit()
(and
on_exit(3))
can be used within a shared library to establish functions
that are called when the shared library is unloaded.
EXAMPLE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
void
bye(void)
{
printf("That was all, folks\n");
}
int
main(void)
{
long a;
int i;
a = sysconf(_SC_ATEXIT_MAX);
printf("ATEXIT_MAX = %ld\n", a);
i = atexit(bye);
if (i != 0) {
fprintf(stderr, "cannot set exit function\n");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
