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ATEXIT(3) Library Functions Manual ATEXIT(3)

atexitregister a function to be called on exit

#include <stdlib.h>

atexit(void (*function)(void));

The atexit() function registers the given function to be called at program exit, whether via exit(3) or via return from the program's main(). Functions so registered are called in reverse order; no arguments are passed. At least 32 functions can always be registered, and more are allowed as long as sufficient memory can be allocated.

atexit() is very difficult to use correctly without creating exit(3)-time races. Unless absolutely necessary, please avoid using it.

The atexit() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

No memory was available to add the function to the list. The existing list of functions is unmodified.


The atexit() function conforms to ANSI X3.159-1989 (“ANSI C89”).

May 31, 2007 OpenBSD-5.1