1 /* Memory allocation on the stack. 2 3 Copyright (C) 1995, 1999, 2001-2004, 2006-2012 Free Software Foundation, 4 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 18 <http://www.gnu.org/licenses/>. 19 */ 20 21 /* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H 22 means there is a real alloca function. */ 23 #ifndef _GL_ALLOCA_H 24 #define _GL_ALLOCA_H 25 26 /* alloca (N) returns a pointer to N bytes of memory 27 allocated on the stack, 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 #ifndef alloca 38 # ifdef __GNUC__ 39 # define alloca __builtin_alloca 40 # elif defined _AIX 41 # define alloca __alloca 42 # elif defined _MSC_VER 43 # include <malloc.h> 44 # define alloca _alloca 45 # elif defined __DECC && defined __VMS 46 # define alloca __ALLOCA 47 # elif defined __TANDEM && defined _TNS_E_TARGET 48 # ifdef __cplusplus 49 extern "C" 50 # endif 51 void *_alloca (unsigned short); 52 # pragma intrinsic (_alloca) 53 # define alloca _alloca 54 # else 55 # include <stddef.h> 56 # ifdef __cplusplus 57 extern "C" 58 # endif 59 void *alloca (size_t); 60 # endif 61 #endif 62 63 #endif /* _GL_ALLOCA_H */ 64