sysdeps/generic/morecore.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 97 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
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) 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 GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _MALLOC_INTERNAL
  20 #define _MALLOC_INTERNAL
  21 #include <malloc.h>
  22 #endif
  23
  24 #ifndef __GNU_LIBRARY__
  25 #define __sbrk  sbrk
  26 #endif
  27
  28 #ifdef __GNU_LIBRARY__
  29 /* It is best not to declare this and cast its result on foreign operating
  30    systems with potentially hostile include files.  */
  31
  32 #include <stddef.h>
  33 extern __ptr_t __sbrk __P ((ptrdiff_t increment));
  34 #endif
  35
  36 #ifndef NULL
  37 #define NULL 0
  38 #endif
  39
  40 /* Allocate INCREMENT more bytes of data space,
  41    and return the start of data space, or NULL on errors.
  42    If INCREMENT is negative, shrink data space.  */
  43 __ptr_t
  44 __default_morecore (increment)
  45      __malloc_ptrdiff_t increment;
  46 {
  47   __ptr_t result = (__ptr_t) __sbrk (increment);
  48   if (result == (__ptr_t) -1)
  49     return NULL;
  50   return result;
  51 }