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

atexit(3C)						   Standard C Library Functions 						atexit(3C)

NAME

       atexit - register a function to run at process termination or object unloading

SYNOPSIS

       #include <stdlib.h>

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

DESCRIPTION

       The atexit() function registers the function pointed to by func to be called without arguments on normal termination of the program or when
       the object defining the function is unloaded.

       Normal termination occurs by either a call to the exit(3C) function or a return from  main().  Object  unloading  occurs  when  a  call	to
       dlclose(3C) results in the object becoming unreferenced.

       The  number  of functions that may be registered with atexit() is limited only by available memory (refer to the _SC_ATEXIT_MAX argument of
       sysconf(3C)).

       After a successful call to any of the exec(2) functions, any functions previously registered by atexit() are no longer registered.

       On process exit, functions are called in the reverse order of their registration. On  object  unloading,  any  functions  belonging  to	an
       unloadable object are called in the reverse order of their registration.

RETURN VALUES

       Upon successful completion, the atexit() function returns 0. Otherwise, it returns a non-zero value.

ERRORS

       The atexit() function may fail if:

       ENOMEM	       Insufficient storage space is available.

USAGE

       The functions registered by a call to atexit() must return to ensure that all registered functions are called.

       There is no way for an application to tell how many functions have already been registered with atexit().

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       exec(2), dlclose(3C), exit(3C), sysconf(3C), attributes(5)

SunOS 5.10							    25 May 2001 							atexit(3C)