xatexit.c revision 130562 
1/*
2 * Copyright (c) 1990 Regents of the University of California.
3 * All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8
9/*
10
11@deftypefun int xatexit (void (*@var{fn}) (void))
12
13Behaves as the standard @code{atexit} function, but with no limit on
14the number of registered functions.  Returns 0 on success, or @minus{}1 on
15failure.  If you use @code{xatexit} to register functions, you must use
16@code{xexit} to terminate your program.
17
18@end deftypefun
19
20*/
21
22/* Adapted from newlib/libc/stdlib/{,at}exit.[ch].
23   If you use xatexit, you must call xexit instead of exit.  */
24
25#include "ansidecl.h"
26#include "libiberty.h"
27
28#include <stdio.h>
29
30#ifdef ANSI_PROTOTYPES
31#include <stddef.h>
32#else
33#define size_t unsigned long
34#endif
35
36#if VMS
37#include <stdlib.h>
38#include <unixlib.h>
39#else
40/* For systems with larger pointers than ints, this must be declared.  */
41PTR malloc PARAMS ((size_t));
42#endif
43
44static void xatexit_cleanup PARAMS ((void));
45
46/* Pointer to function run by xexit.  */
47extern void (*_xexit_cleanup) PARAMS ((void));
48
49#define	XATEXIT_SIZE 32
50
51struct xatexit {
52	struct	xatexit *next;		/* next in list */
53	int	ind;			/* next index in this table */
54	void	(*fns[XATEXIT_SIZE]) PARAMS ((void));	/* the table itself */
55};
56
57/* Allocate one struct statically to guarantee that we can register
58   at least a few handlers.  */
59static struct xatexit xatexit_first;
60
61/* Points to head of LIFO stack.  */
62static struct xatexit *xatexit_head = &xatexit_first;
63
64/* Register function FN to be run by xexit.
65   Return 0 if successful, -1 if not.  */
66
67int
68xatexit (fn)
69     void (*fn) PARAMS ((void));
70{
71  register struct xatexit *p;
72
73  /* Tell xexit to call xatexit_cleanup.  */
74  if (!_xexit_cleanup)
75    _xexit_cleanup = xatexit_cleanup;
76
77  p = xatexit_head;
78  if (p->ind >= XATEXIT_SIZE)
79    {
80      if ((p = (struct xatexit *) malloc (sizeof *p)) == NULL)
81	return -1;
82      p->ind = 0;
83      p->next = xatexit_head;
84      xatexit_head = p;
85    }
86  p->fns[p->ind++] = fn;
87  return 0;
88}
89
90/* Call any cleanup functions.  */
91
92static void
93xatexit_cleanup ()
94{
95  register struct xatexit *p;
96  register int n;
97
98  for (p = xatexit_head; p; p = p->next)
99    for (n = p->ind; --n >= 0;)
100      (*p->fns[n]) ();
101}
102