#include <stdlib.h>

int atexit(void (*func)(void));


Partially implemented


IEEE Std 1003.1-2017


The purpose is to register a function to run at process termination. 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.

Return value

Upon successful completion, atexit() shall return 0, otherwise, it shall return a non-zero value.


No errors are defined.



Known bugs


See Also

  1. Standard library functions
  2. Table of Contents