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glibc  2.9
alloca_cutoff.c
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00001 /* Determine whether block of given size can be allocated on the stack or not.
00002    Copyright (C) 2002 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public License as
00007    published by the Free Software Foundation; either version 2.1 of the
00008    License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; see the file COPYING.LIB.  If not,
00017    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00018    Boston, MA 02111-1307, USA.  */
00019 
00020 #include <alloca.h>
00021 #include <stdlib.h>
00022 #include <sys/param.h>
00023 #include <pthreadP.h>
00024 
00025 
00026 int
00027 __libc_alloca_cutoff (size_t size)
00028 {
00029   return size <= (MIN (__MAX_ALLOCA_CUTOFF,
00030                      THREAD_GETMEM (THREAD_SELF, stackblock_size) / 4
00031                      /* The main thread, before the thread library is
00032                        initialized, has zero in the stackblock_size
00033                        element.  Since it is the main thread we can
00034                        assume the maximum available stack space.  */
00035                      ?: __MAX_ALLOCA_CUTOFF * 4));
00036 }