sysdeps/generic/morecore.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 2, or (at your option)
   7 any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with the GNU C Library; see the file COPYING.  If not, write to
  16 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 #ifndef _MALLOC_INTERNAL
  19 #define _MALLOC_INTERNAL
  20 #include <malloc.h>
  21 #endif
  22
  23 #ifndef __GNU_LIBRARY__
  24 #define __sbrk  sbrk
  25 #endif
  26
  27 #ifdef __GNU_LIBRARY__
  28 /* It is best not to declare this and cast its result on foreign operating
  29    systems with potentially hostile include files.  */
  30
  31 #include <stddef.h>
  32 extern __ptr_t __sbrk __P ((ptrdiff_t increment));
  33 #endif
  34
  35 #ifndef NULL
  36 #define NULL 0
  37 #endif
  38
  39 /* Allocate INCREMENT more bytes of data space,
  40    and return the start of data space, or NULL on errors.
  41    If INCREMENT is negative, shrink data space.  */
  42 __ptr_t
  43 __default_morecore (increment)
  44      __malloc_ptrdiff_t increment;
  45 {
  46   __ptr_t result = (__ptr_t) __sbrk (increment);
  47   if (result == (__ptr_t) -1)
  48     return NULL;
  49   return result;
  50 }