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