gl/xalloc.h

   1 /* xalloc.h -- malloc with out-of-memory checking
   2
   3    Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   4    1999, 2000, 2003, 2004 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 #ifndef XALLOC_H_
  21 # define XALLOC_H_
  22
  23 # include <stddef.h>
  24
  25
  26 # ifdef __cplusplus
  27 extern "C" {
  28 # endif
  29
  30
  31 # ifndef __attribute__
  32 #  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
  33 #   define __attribute__(x)
  34 #  endif
  35 # endif
  36
  37 # ifndef ATTRIBUTE_NORETURN
  38 #  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
  39 # endif
  40
  41 /* This function is always triggered when memory is exhausted.
  42    It must be defined by the application, either explicitly
  43    or by using gnulib's xalloc-die module.  This is the
  44    function to call when one wants the program to die because of a
  45    memory allocation failure.  */
  46 extern void xalloc_die (void) ATTRIBUTE_NORETURN;
  47
  48 void *xmalloc (size_t s);
  49 void *xnmalloc (size_t n, size_t s);
  50 void *xzalloc (size_t s);
  51 void *xcalloc (size_t n, size_t s);
  52 void *xrealloc (void *p, size_t s);
  53 void *xnrealloc (void *p, size_t n, size_t s);
  54 void *x2realloc (void *p, size_t *pn);
  55 void *x2nrealloc (void *p, size_t *pn, size_t s);
  56 void *xmemdup (void const *p, size_t s);
  57 char *xstrdup (char const *str);
  58
  59 /* Return 1 if an array of N objects, each of size S, cannot exist due
  60    to size arithmetic overflow.  S must be positive and N must be
  61    nonnegative.  This is a macro, not an inline function, so that it
  62    works correctly even when SIZE_MAX < N.
  63
  64    By gnulib convention, SIZE_MAX represents overflow in size
  65    calculations, so the conservative dividend to use here is
  66    SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value.
  67    However, malloc (SIZE_MAX) fails on all known hosts where
  68    sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for
  69    exactly-SIZE_MAX allocations on such hosts; this avoids a test and
  70    branch when S is known to be 1.  */
  71 # define xalloc_oversized(n, s) \
  72     ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
  73
  74 # ifdef __cplusplus
  75 }
  76 # endif
  77
  78
  79 #endif /* !XALLOC_H_ */