1/* Memory allocation on the stack.
2
3   Copyright (C) 1995, 1999, 2001-2004, 2006-2022 Free Software Foundation,
4   Inc.
5
6   This file is free software: you can redistribute it and/or modify
7   it under the terms of the GNU Lesser General Public License as
8   published by the Free Software Foundation; either version 2.1 of the
9   License, or (at your option) any later version.
10
11   This file 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
14   GNU Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
18
19/* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
20   means there is a real alloca function.  */
21#ifndef _GL_ALLOCA_H
22#define _GL_ALLOCA_H
23
24/* alloca (N) returns a pointer to N bytes of memory
25   allocated on the stack, which will last until the function returns.
26   Use of alloca should be avoided:
27     - inside arguments of function calls - undefined behaviour,
28     - in inline functions - the allocation may actually last until the
29       calling function returns,
30     - for huge N (say, N >= 65536) - you never know how large (or small)
31       the stack is, and when the stack cannot fulfill the memory allocation
32       request, the program just crashes.
33 */
34
35#ifndef alloca
36  /* Some version of mingw have an <alloca.h> that causes trouble when
37     included after 'alloca' gets defined as a macro.  As a workaround,
38     include this <alloca.h> first and define 'alloca' as a macro afterwards
39     if needed.  */
40# if defined __GNUC__ && (defined _WIN32 && ! defined __CYGWIN__) && @HAVE_ALLOCA_H@
41#  include_next <alloca.h>
42# endif
43#endif
44#ifndef alloca
45# if defined __GNUC__ || (__clang_major__ >= 4)
46#  define alloca __builtin_alloca
47# elif defined _AIX
48#  define alloca __alloca
49# elif defined _MSC_VER
50#  include <malloc.h>
51#  define alloca _alloca
52# elif defined __DECC && defined __VMS
53#  define alloca __ALLOCA
54# elif defined __TANDEM && defined _TNS_E_TARGET
55#  ifdef  __cplusplus
56extern "C"
57#  endif
58void *_alloca (unsigned short);
59#  pragma intrinsic (_alloca)
60#  define alloca _alloca
61# elif defined __MVS__
62#  include <stdlib.h>
63# else
64#  include <stddef.h>
65#  ifdef  __cplusplus
66extern "C"
67#  endif
68void *alloca (size_t);
69# endif
70#endif
71
72#endif /* _GL_ALLOCA_H */
73