xref: /netbsd-src/external/gpl2/gettext/include/alloca.h (revision cbffe7eabbcc2eb7af2c92f13ea95347456c3ed2)
1 /* Memory allocation on the stack.
2    Copyright (C) 1995, 1999, 2001-2005 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 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    General Public License for more details.
13 
14    You should have received a copy of the GNU General Public
15    License along with this program; if not, write to the Free Software
16    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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 /* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
24    means there is a real alloca function.  */
25 #ifndef _GNULIB_ALLOCA_H
26 #define _GNULIB_ALLOCA_H
27 
28 /* alloca(N) returns a pointer (void* or char*) to N bytes of memory
29    allocated on the stack, and which will last until the function returns.
30    Use of alloca should be avoided:
31      - inside arguments of function calls - undefined behaviour,
32      - in inline functions - the allocation may actually last until the
33        calling function returns,
34      - for huge N (say, N >= 65536) - you never know how large (or small)
35        the stack is, and when the stack cannot fulfill the memory allocation
36        request, the program just crashes.
37  */
38 
39 #if defined(__GNUC__) || defined(__lint__)
40 # ifndef alloca
41 #  define alloca __builtin_alloca
42 # endif
43 #else
44 # ifdef _MSC_VER
45 #  include <malloc.h>
46 #  define alloca _alloca
47 # else
48 #  if HAVE_ALLOCA_H
49 #   include <alloca.h>
50 #  else
51 #   ifdef _AIX
52  #pragma alloca
53 #   else
54 #    ifdef __hpux /* This section must match that of bison generated files. */
55 #     ifdef __cplusplus
56 extern "C" void *alloca (unsigned int);
57 #     else /* not __cplusplus */
58 extern void *alloca ();
59 #     endif /* not __cplusplus */
60 #    else /* not __hpux */
61 #     ifndef alloca
62 extern char *alloca ();
63 #     endif
64 #    endif /* __hpux */
65 #   endif
66 #  endif
67 # endif
68 #endif
69 
70 #endif /* _GNULIB_ALLOCA_H */
71