atexit — register a function to be called at normal process termination
#include <stdlib.h>
int
atexit( |
void | (*function)(void)); |
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.
The atexit() function
returns the value 0 if successful; otherwise it returns a
nonzero value.
Functions registered using atexit() (and on_exit(3)) are not called
if a process terminates abnormally because of the delivery of
a signal.
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.
#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);
}