exit.c

标准c库代码,可以应用于各个系统提供了大量的基本函数

/*
 * Copyright (c) 1990 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

/*
FUNCTION
<<exit>>---end program execution

INDEX
	exit

ANSI_SYNOPSIS
	#include <stdlib.h>
	void exit(int <[code]>);

TRAD_SYNOPSIS
	#include <stdlib.h>
	void exit(<[code]>)
	int <[code]>;

DESCRIPTION
Use <<exit>> to return control from a program to the host operating
environment.  Use the argument <[code]> to pass an exit status to the
operating environment: two particular values, <<EXIT_SUCCESS>> and
<<EXIT_FAILURE>>, are defined in `<<stdlib.h>>' to indicate success or
failure in a portable fashion.

<<exit>> does two kinds of cleanup before ending execution of your
program.  First, it calls all application-defined cleanup functions
you have enrolled with <<atexit>>.  Second, files and streams are
cleaned up: any pending output is delivered to the host system, each
open file or stream is closed, and files created by <<tmpfile>> are
deleted.

RETURNS
<<exit>> does not return to its caller.

PORTABILITY
ANSI C requires <<exit>>, and specifies that <<EXIT_SUCCESS>> and
<<EXIT_FAILURE>> must be defined.

Supporting OS subroutines required: <<_exit>>.
*/

#include <stdlib.h>
#include <reent.h>

#ifndef _REENT_ONLY

/*
 * Exit, flushing stdio buffers if necessary.
 */

void 
_DEFUN (exit, (code),
	int code)
{
  register struct _atexit *p;
  register int n;

  for (p = _REENT->_atexit; p; p = p->_next)
    for (n = p->_ind; --n >= 0;)
      (*p->_fns[n]) ();
  if (_REENT->__cleanup)
    (*_REENT->__cleanup) (_REENT);
  _exit (code);
}

#endif