#include <stdlib.h>
int atexit(void (*func)(void));
The atexit() function shall register the function pointed to by func, to be called without arguments at normal program termination. At normal program termination, all functions registered by the atexit() function shall be called, in the reverse order of their registration, except that a function is called after any previously registered functions that had already been called at the time it was registered. Normal termination occurs either by a call to exit() or a return from main().
At least 32 functions can be registered with atexit().
After a successful call to any of the exec functions, any functions previously registered by atexit() shall no longer be registered.
Upon successful completion, atexit() shall return 0; otherwise, it shall return a non-zero value.
No errors are defined.
The following sections are informative.
The functions registered by a call to atexit() must return to ensure that all registered functions are called.
The application should call sysconf() to obtain the value of {ATEXIT_MAX}, the number of functions that can be registered. There is no way for an application to tell how many functions have already been registered with atexit().
exit() , sysconf() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>