malloc/morecore.c

   1 /* Copyright (C) 1991-2020 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  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 # include <stdlib.h>
  33 extern void *__sbrk (ptrdiff_t increment) __THROW;
  34 libc_hidden_proto (__sbrk)
  35 #endif
  36
  37 #ifndef NULL
  38 # define NULL 0
  39 #endif
  40
  41 /* Allocate INCREMENT more bytes of data space,
  42    and return the start of data space, or NULL on errors.
  43    If INCREMENT is negative, shrink data space.  */
  44 void *
  45 __default_morecore (ptrdiff_t increment)
  46 {
  47   void *result = (void *) __sbrk (increment);
  48   if (result == (void *) -1)
  49     return NULL;
  50
  51   return result;
  52 }
  53 libc_hidden_def (__default_morecore)