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 
13 Behaves as the standard @code{atexit} function, but with no limit on
14 the number of registered functions.  Returns 0 on success, or @minus{}1 on
15 failure.  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.  */
41 PTR malloc PARAMS ((size_t));
42 #endif
43 
44 static void xatexit_cleanup PARAMS ((void));
45 
46 /* Pointer to function run by xexit.  */
47 extern void (*_xexit_cleanup) PARAMS ((void));
48 
49 #define	XATEXIT_SIZE 32
50 
51 struct 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.  */
59 static struct xatexit xatexit_first;
60 
61 /* Points to head of LIFO stack.  */
62 static 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 
67 int
68 xatexit (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 
92 static void
xatexit_cleanup()93 xatexit_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