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.
The same function may be registered multiple times: it is called once for each registration.
POSIX.1 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.
#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);
}