1 /* Memory allocation on the stack.
3 Copyright (C) 1995, 1999, 2001-2004, 2006-2019 Free Software Foundation,
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 2, or (at your option)
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 <https://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. */
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.
39 /* Some version of mingw have an <alloca.h> that causes trouble when
40 included after 'alloca' gets defined as a macro. As a workaround, include
41 this <alloca.h> first and define 'alloca' as a macro afterwards. */
42 # if (defined _WIN32 && ! defined __CYGWIN__) && @HAVE_ALLOCA_H@
43 # include_next <alloca.h>
45 # define alloca __builtin_alloca
47 # define alloca __alloca
48 # elif defined _MSC_VER
50 # define alloca _alloca
51 # elif defined __DECC && defined __VMS
52 # define alloca __ALLOCA
53 # elif defined __TANDEM && defined _TNS_E_TARGET
57 void *_alloca (unsigned short);
58 # pragma intrinsic (_alloca)
59 # define alloca _alloca
60 # elif defined __MVS__
67 void *alloca (size_t);
71 #endif /* _GL_ALLOCA_H */