1 /* Memory allocation on the stack. 2 Copyright (C) 1995, 1999, 2001-2005 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 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 General Public License for more details. 13 14 You should have received a copy of the GNU General Public 15 License along with this program; if not, write to the Free Software 16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 /* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H 24 means there is a real alloca function. */ 25 #ifndef _GNULIB_ALLOCA_H 26 #define _GNULIB_ALLOCA_H 27 28 /* alloca(N) returns a pointer (void* or char*) to N bytes of memory 29 allocated on the stack, and which will last until the function returns. 30 Use of alloca should be avoided: 31 - inside arguments of function calls - undefined behaviour, 32 - in inline functions - the allocation may actually last until the 33 calling function returns, 34 - for huge N (say, N >= 65536) - you never know how large (or small) 35 the stack is, and when the stack cannot fulfill the memory allocation 36 request, the program just crashes. 37 */ 38 39 #if defined(__GNUC__) || defined(__lint__) 40 # ifndef alloca 41 # define alloca __builtin_alloca 42 # endif 43 #else 44 # ifdef _MSC_VER 45 # include <malloc.h> 46 # define alloca _alloca 47 # else 48 # if HAVE_ALLOCA_H 49 # include <alloca.h> 50 # else 51 # ifdef _AIX 52 #pragma alloca 53 # else 54 # ifdef __hpux /* This section must match that of bison generated files. */ 55 # ifdef __cplusplus 56 extern "C" void *alloca (unsigned int); 57 # else /* not __cplusplus */ 58 extern void *alloca (); 59 # endif /* not __cplusplus */ 60 # else /* not __hpux */ 61 # ifndef alloca 62 extern char *alloca (); 63 # endif 64 # endif /* __hpux */ 65 # endif 66 # endif 67 # endif 68 #endif 69 70 #endif /* _GNULIB_ALLOCA_H */ 71