NAME
atexit —
register a function to be called on
exit
SYNOPSIS
#include
<stdlib.h>
int
atexit(void
(*function)(void));
DESCRIPTION
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.
If a shared object is unloaded from process memory
using dlclose(3), then any functions registered by calling
atexit()
from that shared object will be called in reverse order and unregistered.
Note that it is the source of the call to atexit()
that matters, not the source of the function that was registered.
atexit()
is very difficult to use correctly without creating
exit(3)-time races. Unless absolutely necessary, avoid using it.
RETURN VALUES
The atexit function returns the value 0 if
successful; otherwise a non-zero value is returned and the global variable
errno is set to indicate the error.
ERRORS
- [
ENOMEM] - No memory was available to add the function to the list. The existing list of functions is unmodified.
SEE ALSO
STANDARDS
The atexit() function conforms to
ANSI X3.159-1989
(“ANSI C89”).
Setting errno on error and the behavior when a shared object is unloaded are extensions to that standard.