1 /* Memory allocation on the stack.
2    Copyright (C) 1995, 1999, 2001-2007 Free Software Foundation, Inc.
3 
4    This program is free software: you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 3 of the License, or
7    (at your option) 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
12    GNU General Public License for more details.
13 
14    You should have received a copy of the GNU General Public License
15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
16 
17 /* When this file is included, it may be preceded only by preprocessor
18    declarations.  Thanks to AIX.  Therefore we include it right after
19    "config.h", not later.  */
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 (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 #ifndef alloca
38 # ifdef __GNUC__
39 #   define alloca __builtin_alloca
40 # else
41 #  ifdef _MSC_VER
42 #   include <malloc.h>
43 #   define alloca _alloca
44 #  else
45 #   if HAVE_ALLOCA_H
46 #    include <alloca.h>
47 #   else
48 #    ifdef _AIX
49  #pragma alloca
50 #    else
51 #     ifdef __hpux /* This section must match that of bison generated files. */
52 #      ifdef __cplusplus
53 extern "C" void *alloca (unsigned int);
54 #      else /* not __cplusplus */
55 extern void *alloca ();
56 #      endif /* not __cplusplus */
57 #     else /* not __hpux */
58 #      ifndef alloca
59 extern char *alloca ();
60 #      endif
61 #     endif /* __hpux */
62 #    endif
63 #   endif
64 #  endif
65 # endif
66 #endif
67 
68 #endif /* _GL_ALLOCA_H */
69