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 /* 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.  */
  23 PTR malloc PARAMS ((size_t));
  24
  25 static void xatexit_cleanup PARAMS ((void));
  26
  27 /* Pointer to function run by xexit.  */
  28 extern void (*_xexit_cleanup) PARAMS ((void));
  29
  30 #define XATEXIT_SIZE 32
  31
  32 struct 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.  */
  40 static struct xatexit xatexit_first;
  41
  42 /* Points to head of LIFO stack.  */
  43 static 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
  48 int
  49 xatexit (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
  73 static void
  74 xatexit_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 }