1/* Memory allocation on the stack. 2 Copyright (C) 1995, 1999, 2001-2003 Free Software Foundation, Inc. 3 4 This program is free software; you can redistribute it and/or modify it 5 under the terms of the GNU Library General Public License as published 6 by the Free Software Foundation; either version 2, or (at your option) 7 any later version. 8 9 This program 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 GNU 12 Library General Public License for more details. 13 14 You should have received a copy of the GNU Library General Public 15 License along with this program; if not, write to the Free Software 16 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 17 USA. */ 18 19/* When this file is included, it may be preceded only by preprocessor 20 declarations. Thanks to AIX. Therefore we include it right after 21 "config.h", not later. */ 22 23#ifndef _ALLOCA_H 24#define _ALLOCA_H 25 26/* alloca(N) returns a pointer (void* or char*) to N bytes of memory 27 allocated on the stack, and which will last until the function returns. 28 Use of alloca should be avoided: 29 - inside arguments of function calls - undefined behaviour, 30 - in inline functions - the allocation may actually last until the 31 calling function returns, 32 - for huge N (say, N >= 65536) - you never know how large (or small) 33 the stack is, and when the stack cannot fulfill the memory allocation 34 request, the program just crashes. 35 */ 36 37#ifdef __GNUC__ 38# ifndef alloca 39# define alloca __builtin_alloca 40# endif 41#else 42# ifdef _MSC_VER 43# include <malloc.h> 44# define alloca _alloca 45# else 46# if HAVE_ALLOCA_H 47# include <alloca.h> 48# else 49# ifdef _AIX 50 #pragma alloca 51# else 52# ifdef __hpux /* This section must match that of bison generated files. */ 53# ifdef __cplusplus 54extern "C" void *alloca (unsigned int); 55# else /* not __cplusplus */ 56extern void *alloca (); 57# endif /* not __cplusplus */ 58# else /* not __hpux */ 59# ifndef alloca 60extern char *alloca (); 61# endif 62# endif /* __hpux */ 63# endif 64# endif 65# endif 66#endif 67 68#endif /* _ALLOCA_H */ 69