atexit(3) BSD Library Functions Manual atexit(3)
NAME
atexit -- register a function to be called on exit
SYNOPSIS
#include <stdlib.h>
int
atexit(void (*func)(void));
int
atexit_b(void (^block)(void));
DESCRIPTION
The atexit() function registers the function func to be called at program
exit, whether via exit(3) or via return from the program's main(). Func-
tions so registered are called in reverse order; no arguments are passed.
The atexit_b() function is like atexit() except the callback is a block
pointer instead of a function pointer.
Note: The Block_copy() function (defined in <Blocks.h>) is used by
atexit_b() to make a copy of the block, especially for the case
when a stack-based block might go out of scope when the subroutine
returns.
These callbacks must not call exit(); if it should be necessary to termi-
nate the process while in such a function, the _exit(2) function should
be used. (Alternatively, the callbacks may cause abnormal process termi-
nation, for example by calling abort(3).)
At least 32 callbacks can always be registered; more are allowed as long
as sufficient memory can be allocated.
RETURN VALUES
The atexit() and atexit_b() functions return the value 0 if successful;
otherwise the value -1 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
exit(3)
STANDARDS
The atexit() function conforms to ISO/IEC 9899:1990 (``ISO C90'').
BSD May 20, 2008 BSD
Mac OS X 10.6 - Generated Thu Sep 17 20:18:30 CDT 2009