97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/*
|
|
* Copyright (c) 1990 Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* %sccs.include.redist.c%
|
|
*
|
|
* This function is a modified version of atexit.c
|
|
*/
|
|
|
|
/*
|
|
FUNCTION
|
|
<<on_exit>>---request execution of function with argument at program exit
|
|
|
|
INDEX
|
|
on_exit
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <stdlib.h>
|
|
int on_exit (void (*<[function]>)(int, void *), void *<[arg]>);
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <stdlib.h>
|
|
int on_exit ((<[function]>, <[arg]>)
|
|
void (*<[function]>)(int, void *);
|
|
void *<[arg]>;
|
|
|
|
DESCRIPTION
|
|
You can use <<on_exit>> to enroll functions in a list of functions that
|
|
will be called when your program terminates normally. The argument is
|
|
a pointer to a user-defined function which takes two arguments. The
|
|
first is the status code passed to exit and the second argument is of type
|
|
pointer to void. The function must not return a result. The value
|
|
of <[arg]> is registered and passed as the argument to <[function]>.
|
|
|
|
The functions are kept in a LIFO stack; that is, the last function
|
|
enrolled by <<atexit>> or <<on_exit>> will be the first to execute when
|
|
your program exits. You can intermix functions using <<atexit>> and
|
|
<<on_exit>>.
|
|
|
|
There is no built-in limit to the number of functions you can enroll
|
|
in this list; however, after every group of 32 functions is enrolled,
|
|
<<atexit>>/<<on_exit>> will call <<malloc>> to get space for the next part
|
|
of the list. The initial list of 32 functions is statically allocated, so
|
|
you can always count on at least that many slots available.
|
|
|
|
RETURNS
|
|
<<on_exit>> returns <<0>> if it succeeds in enrolling your function,
|
|
<<-1>> if it fails (possible only if no space was available for
|
|
<<malloc>> to extend the list of functions).
|
|
|
|
PORTABILITY
|
|
<<on_exit>> is a non-standard glibc extension
|
|
|
|
Supporting OS subroutines required: None
|
|
*/
|
|
|
|
#include <stddef.h>
|
|
#include <stdlib.h>
|
|
#include <reent.h>
|
|
|
|
/*
|
|
* Register a function to be performed at exit.
|
|
*/
|
|
|
|
int
|
|
_DEFUN (on_exit,
|
|
(fn, arg),
|
|
_VOID _EXFUN ((*fn), (int, _PTR)) _AND
|
|
_PTR arg)
|
|
{
|
|
register struct _atexit *p;
|
|
void (*x)(void) = (void (*)(void))fn;
|
|
|
|
/* _REENT_SMALL on_exit() doesn't allow more than the required 32 entries. */
|
|
#ifndef _REENT_SMALL
|
|
if ((p = _REENT->_atexit) == NULL)
|
|
_REENT->_atexit = p = &_REENT->_atexit0;
|
|
if (p->_ind >= _ATEXIT_SIZE)
|
|
{
|
|
if ((p = (struct _atexit *) malloc (sizeof *p)) == NULL)
|
|
return -1;
|
|
p->_ind = 0;
|
|
p->_fntypes = 0;
|
|
p->_next = _REENT->_atexit;
|
|
_REENT->_atexit = p;
|
|
}
|
|
#else
|
|
p = &_REENT->_atexit;
|
|
if (p->_ind >= _ATEXIT_SIZE)
|
|
return -1;
|
|
#endif
|
|
p->_fntypes |= (1 << p->_ind);
|
|
p->_fnargs[p->_ind] = arg;
|
|
p->_fns[p->_ind++] = x;
|
|
return 0;
|
|
}
|