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#ifdef HAVE_CONFIG_H
26#include "config.h"
27#endif
28#include "ansidecl.h"
29#include "libiberty.h"
30
31#include <stdio.h>
32
33#include <stddef.h>
34
35#if VMS
36#include <stdlib.h>
37#include <unixlib.h>
38#else
39/* For systems with larger pointers than ints, this must be declared. */
40void *malloc (size_t);
41#endif
42
43static void xatexit_cleanup (void);
44
45/* Pointer to function run by xexit. */
46extern void (*_xexit_cleanup) (void);
47
48#define XATEXIT_SIZE 32
49
50struct xatexit {
51 struct xatexit *next; /* next in list */
52 int ind; /* next index in this table */
53 void (*fns[XATEXIT_SIZE]) (void); /* the table itself */
54};
55
56/* Allocate one struct statically to guarantee that we can register
57 at least a few handlers. */
58static struct xatexit xatexit_first;
59
60/* Points to head of LIFO stack. */
61static struct xatexit *xatexit_head = &xatexit_first;
62
63/* Register function FN to be run by xexit.
64 Return 0 if successful, -1 if not. */
65
66int
67xatexit (void (*fn) (void))
68{
69 register struct xatexit *p;
70
71 /* Tell xexit to call xatexit_cleanup. */
72 if (!_xexit_cleanup)
73 _xexit_cleanup = xatexit_cleanup;
74
75 p = xatexit_head;
76 if (p->ind >= XATEXIT_SIZE)
77 {
78 if ((p = (struct xatexit *) malloc (sizeof *p)) == NULL)
79 return -1;
80 p->ind = 0;
81 p->next = xatexit_head;
82 xatexit_head = p;
83 }
84 p->fns[p->ind++] = fn;
85 return 0;
86}
87
88/* Call any cleanup functions. */
89
90static void
91xatexit_cleanup (void)
92{
93 register struct xatexit *p;
94 register int n;
95
96 for (p = xatexit_head; p; p = p->next)
97 for (n = p->ind; --n >= 0;)
98 (*p->fns[n]) ();
99}
100

source code of libiberty/xatexit.c