coreutils/lib/alloca_.h

/* Memory allocation on the stack.

   Copyright (C) 1995, 1999, 2001, 2002, 2003, 2004 Free Software
   Foundation, Inc.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published
   by the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public
   License along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA.  */

/* When this file is included, it may be preceded only by preprocessor
   declarations.  Thanks to AIX.  Therefore we include it right after
   "config.h", not later.  */

#ifndef _ALLOCA_H
# define _ALLOCA_H

/* alloca (N) returns a pointer to N bytes of memory
   allocated on the stack, which will last until the function returns.
   Use of alloca should be avoided:
     - inside arguments of function calls - undefined behaviour,
     - in inline functions - the allocation may actually last until the
       calling function returns,
     - for huge N (say, N >= 65536) - you never know how large (or small)
       the stack is, and when the stack cannot fulfill the memory allocation
       request, the program just crashes.
 */

#ifdef __GNUC__
# define alloca __builtin_alloca
#elif defined _AIX
# define alloca __alloca
#elif defined _MSC_VER
# include <malloc.h>
# define alloca _alloca
#else
# include <stddef.h>
# ifdef  __cplusplus
extern "C"
# endif
void *alloca (size_t);
#endif

#endif /* _ALLOCA_H */