atexit(3) [osx man page]

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().
     Functions 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 terminate the process while in such a function, the _exit(2) function
     should be used.  (Alternatively, the callbacks may cause abnormal process termination, 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