sysdeps/generic/sbrk.c

   1 /* Copyright (C) 1991, 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 #include <ansidecl.h>
  19
  20 /* Defined in brk.c.  */
  21 extern PTR __curbrk;
  22 extern int EXFUN(__brk, (PTR addr));
  23
  24 /* Extend the process's data space by INCREMENT.
  25    If INCREMENT is negative, shrink data space by - INCREMENT.
  26    Return start of new space allocated, or -1 for errors.  */
  27 PTR
  28 DEFUN(__sbrk, (increment), int increment)
  29 {
  30   char *oldbrk;
  31
  32   if (increment == 0)
  33     return __curbrk;
  34
  35   oldbrk = __curbrk;
  36   if (__brk(oldbrk + increment) < 0)
  37     return (PTR) -1;
  38
  39   return oldbrk;
  40 }
  41
  42 weak_alias (__sbrk, sbrk)