1  /* Determine whether block of given size can be allocated on the stack or not.
       2     Copyright (C) 2002-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; see the file COPYING.LIB.  If
      17     not, see <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <alloca.h>
      20  #include <stdlib.h>
      21  #include <sys/param.h>
      22  #include <pthreadP.h>
      23  
      24  
      25  int
      26  __libc_alloca_cutoff (size_t size)
      27  {
      28    return size <= (MIN (__MAX_ALLOCA_CUTOFF,
      29  		       THREAD_GETMEM (THREAD_SELF, stackblock_size) / 4
      30  		       /* The main thread, before the thread library is
      31  			  initialized, has zero in the stackblock_size
      32  			  element.  Since it is the main thread we can
      33  			  assume the maximum available stack space.  */
      34  		       ?: __MAX_ALLOCA_CUTOFF * 4));
      35  }
      36  libc_hidden_def (__libc_alloca_cutoff)