| 1 | /* Memory allocation on the stack. |
| 2 | |
| 3 | Copyright (C) 1995, 1999, 2001-2004, 2006-2020 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 | <https://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 | /* Some version of mingw have an <alloca.h> that causes trouble when |
| 40 | included after 'alloca' gets defined as a macro. As a workaround, include |
| 41 | this <alloca.h> first and define 'alloca' as a macro afterwards. */ |
| 42 | # if (defined _WIN32 && ! defined __CYGWIN__) && @HAVE_ALLOCA_H@ |
| 43 | # include_next <alloca.h> |
| 44 | # endif |
| 45 | # define alloca __builtin_alloca |
| 46 | # elif defined _AIX |
| 47 | # define alloca __alloca |
| 48 | # elif defined _MSC_VER |
| 49 | # include <malloc.h> |
| 50 | # define alloca _alloca |
| 51 | # elif defined __DECC && defined __VMS |
| 52 | # define alloca __ALLOCA |
| 53 | # elif defined __TANDEM && defined _TNS_E_TARGET |
| 54 | # ifdef __cplusplus |
| 55 | extern "C" |
| 56 | # endif |
| 57 | void *_alloca (unsigned short); |
| 58 | # pragma intrinsic (_alloca) |
| 59 | # define alloca _alloca |
| 60 | # elif defined __MVS__ |
| 61 | # include <stdlib.h> |
| 62 | # else |
| 63 | # include <stddef.h> |
| 64 | # ifdef __cplusplus |
| 65 | extern "C" |
| 66 | # endif |
| 67 | void *alloca (size_t); |
| 68 | # endif |
| 69 | #endif |
| 70 | |
| 71 | #endif /* _GL_ALLOCA_H */ |