2.13.4.2 atexit
Declaration:
int atexit(void (*func)(void));
Causes the specified function to be called when the program terminates normally. At least 32 functions can be registered to be called when the program terminates. They are called in a last-in, first-out basis (the last function registered is called first).
On success zero is returned. On failure a nonzero value is returned.