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* Copyright (c) 1990 Regents of the University of California.
* All rights reserved.
* %sccs.include.redist.c%
@deftypefun int xatexit (void (*@var{fn}) (void))
Behaves as the standard @code{atexit} function, but with no limit on
the number of registered functions. Returns 0 on success, or @minus{}1 on
failure. If you use @code{xatexit} to register functions, you must use
@code{xexit} to terminate your program.
@end deftypefun
/* Adapted from newlib/libc/stdlib/{,at}exit.[ch].
If you use xatexit, you must call xexit instead of exit. */
#include "config.h"
#include "ansidecl.h"
#include "libiberty.h"
#include <stdio.h>
#include <stddef.h>
#if VMS
#include <stdlib.h>
#include <unixlib.h>
/* For systems with larger pointers than ints, this must be declared. */
void *malloc (size_t);
static void xatexit_cleanup (void);
/* Pointer to function run by xexit. */
extern void (*_xexit_cleanup) (void);
#define XATEXIT_SIZE 32
struct xatexit {
struct xatexit *next; /* next in list */
int ind; /* next index in this table */
void (*fns[XATEXIT_SIZE]) (void); /* the table itself */
/* Allocate one struct statically to guarantee that we can register
at least a few handlers. */
static struct xatexit xatexit_first;
/* Points to head of LIFO stack. */
static struct xatexit *xatexit_head = &xatexit_first;
/* Register function FN to be run by xexit.
Return 0 if successful, -1 if not. */
xatexit (void (*fn) (void))
register struct xatexit *p;
/* Tell xexit to call xatexit_cleanup. */
if (!_xexit_cleanup)
_xexit_cleanup = xatexit_cleanup;
p = xatexit_head;
if (p->ind >= XATEXIT_SIZE)
if ((p = (struct xatexit *) malloc (sizeof *p)) == NULL)
return -1;
p->ind = 0;
p->next = xatexit_head;
xatexit_head = p;
p->fns[p->ind++] = fn;
return 0;
/* Call any cleanup functions. */
static void
xatexit_cleanup (void)
register struct xatexit *p;
register int n;
for (p = xatexit_head; p; p = p->next)
for (n = p->ind; --n >= 0;)
(*p->fns[n]) ();