libiberty/xatexit.c

   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
  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 }