ATEXIT(P)						     POSIX Programmer's Manual							 ATEXIT(P)

NAME

       atexit - register a function to run at process termination

SYNOPSIS

       #include <stdlib.h>

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

DESCRIPTION

       The atexit() function shall register the function pointed to by func, to be called without arguments at normal program termination. At nor-
       mal program termination, all functions registered by the atexit() function shall be called, in the reverse  order  of  their  registration,
       except that a function is called after any previously registered functions that had already been called at the time it was registered. Nor-
       mal termination occurs either by a call to exit() or a return from main().

       At least 32 functions can be registered with atexit().

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

RETURN VALUE

       Upon successful completion, atexit() shall return 0; otherwise, it shall return a non-zero value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

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

       The application should call sysconf() to obtain the value of {ATEXIT_MAX}, the number of functions that can be registered. There is no  way
       for an application to tell how many functions have already been registered with atexit().

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       exit() , sysconf() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								 ATEXIT(P)