Merge from emacs-24; up to 2012-05-04T19:17:01Z!monnier@iro.umontreal.ca
[emacs.git] / lib / alloca.in.h
blobd20f4b8f1c3d1d82e144dd6ffc9553845d8d369f
1 /* Memory allocation on the stack.
3 Copyright (C) 1995, 1999, 2001-2004, 2006-2012 Free Software Foundation,
4 Inc.
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.
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.
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/>.
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
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.
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
63 #endif /* _GL_ALLOCA_H */