76 lines
2.1 KiB
C
76 lines
2.1 KiB
C
/*
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* Copyright (c) 1990 Regents of the University of California.
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* All rights reserved.
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*
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* %sccs.include.redist.c%
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*
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* This function is a modified version of atexit.c
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*/
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/*
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FUNCTION
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<<on_exit>>---request execution of function with argument at program exit
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INDEX
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on_exit
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SYNOPSIS
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#include <stdlib.h>
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int on_exit (void (*<[function]>)(int, void *), void *<[arg]>);
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DESCRIPTION
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You can use <<on_exit>> to enroll functions in a list of functions that
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will be called when your program terminates normally. The argument is
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a pointer to a user-defined function which takes two arguments. The
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first is the status code passed to exit and the second argument is of type
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pointer to void. The function must not return a result. The value
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of <[arg]> is registered and passed as the argument to <[function]>.
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The functions are kept in a LIFO stack; that is, the last function
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enrolled by <<atexit>> or <<on_exit>> will be the first to execute when
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your program exits. You can intermix functions using <<atexit>> and
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<<on_exit>>.
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There is no built-in limit to the number of functions you can enroll
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in this list; however, after every group of 32 functions is enrolled,
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<<atexit>>/<<on_exit>> will call <<malloc>> to get space for the next part
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of the list. The initial list of 32 functions is statically allocated, so
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you can always count on at least that many slots available.
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RETURNS
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<<on_exit>> returns <<0>> if it succeeds in enrolling your function,
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<<-1>> if it fails (possible only if no space was available for
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<<malloc>> to extend the list of functions).
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PORTABILITY
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<<on_exit>> is a non-standard glibc extension
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Supporting OS subroutines required: None
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*/
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#include <stddef.h>
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#include <stdlib.h>
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#include "atexit.h"
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#ifdef _REENT_SMALL
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#include "on_exit_args.h"
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/* force linking of static instance of _on_exit_args */
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const void * const __on_exit_dummy = &__on_exit_args;
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#endif /* def _REENT_SMALL */
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/*
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* Register a function to be performed at exit.
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*/
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int
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_DEFUN (on_exit,
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(fn, arg),
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_VOID _EXFNPTR(fn, (int, _PTR)),
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_PTR arg)
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{
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return __register_exitproc (__et_onexit, (void (*)(void)) fn, arg, NULL);
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}
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