xatexit.c revision 33965 
1/*
2 * Copyright (c) 1990 Regents of the University of California.
3 * All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8/* Adapted from newlib/libc/stdlib/{,at}exit.[ch].
9   If you use xatexit, you must call xexit instead of exit.  */
10
11#include "ansidecl.h"
12#include "libiberty.h"
13
14#include <stdio.h>
15
16#ifdef __STDC__
17#include <stddef.h>
18#else
19#define size_t unsigned long
20#endif
21
22/* For systems with larger pointers than ints, this must be declared.  */
23PTR malloc PARAMS ((size_t));
24
25static void xatexit_cleanup PARAMS ((void));
26
27/* Pointer to function run by xexit.  */
28extern void (*_xexit_cleanup) PARAMS ((void));
29
30#define	XATEXIT_SIZE 32
31
32struct xatexit {
33	struct	xatexit *next;		/* next in list */
34	int	ind;			/* next index in this table */
35	void	(*fns[XATEXIT_SIZE]) PARAMS ((void));	/* the table itself */
36};
37
38/* Allocate one struct statically to guarantee that we can register
39   at least a few handlers.  */
40static struct xatexit xatexit_first;
41
42/* Points to head of LIFO stack.  */
43static struct xatexit *xatexit_head = &xatexit_first;
44
45/* Register function FN to be run by xexit.
46   Return 0 if successful, -1 if not.  */
47
48int
49xatexit (fn)
50     void (*fn) PARAMS ((void));
51{
52  register struct xatexit *p;
53
54  /* Tell xexit to call xatexit_cleanup.  */
55  if (!_xexit_cleanup)
56    _xexit_cleanup = xatexit_cleanup;
57
58  p = xatexit_head;
59  if (p->ind >= XATEXIT_SIZE)
60    {
61      if ((p = (struct xatexit *) malloc (sizeof *p)) == NULL)
62	return -1;
63      p->ind = 0;
64      p->next = xatexit_head;
65      xatexit_head = p;
66    }
67  p->fns[p->ind++] = fn;
68  return 0;
69}
70
71/* Call any cleanup functions.  */
72
73static void
74xatexit_cleanup ()
75{
76  register struct xatexit *p;
77  register int n;
78
79  for (p = xatexit_head; p; p = p->next)
80    for (n = p->ind; --n >= 0;)
81      (*p->fns[n]) ();
82}
83