gl/alloca_.h

   1 /* Memory allocation on the stack.
   2
   3    Copyright (C) 1995, 1999, 2001, 2002, 2003, 2004, 2006 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published
   8    by the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public
  17    License along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
  21    means there is a real alloca function.  */
  22 #ifndef _GNULIB_ALLOCA_H
  23 # define _GNULIB_ALLOCA_H
  24
  25 /* alloca (N) returns a pointer to N bytes of memory
  26    allocated on the stack, which will last until the function returns.
  27    Use of alloca should be avoided:
  28      - inside arguments of function calls - undefined behaviour,
  29      - in inline functions - the allocation may actually last until the
  30        calling function returns,
  31      - for huge N (say, N >= 65536) - you never know how large (or small)
  32        the stack is, and when the stack cannot fulfill the memory allocation
  33        request, the program just crashes.
  34  */
  35
  36 #ifndef alloca
  37 # ifdef __GNUC__
  38 #  define alloca __builtin_alloca
  39 # elif defined _AIX
  40 #  define alloca __alloca
  41 # elif defined _MSC_VER
  42 #  include <malloc.h>
  43 #  define alloca _alloca
  44 # else
  45 #  include <stddef.h>
  46 #  ifdef  __cplusplus
  47 extern "C"
  48 #  endif
  49 void *alloca (size_t);
  50 # endif
  51 #endif
  52
  53 #endif /* _GNULIB_ALLOCA_H */