75 lines
2.4 KiB
C
75 lines
2.4 KiB
C
|
/* Memory allocation on the stack.
|
||
|
|
|
||
|
|
Copyright (C) 1995, 1999, 2001-2004, 2006-2021 Free Software Foundation,
|
||
|
|
Inc.
|
||
|
|
|
||
|
|
This program is free software; you can redistribute it and/or modify it
|
||
|
|
under the terms of the GNU General Public License as published
|
||
|
|
by the Free Software Foundation; either version 3, or (at your option)
|
||
|
|
any later version.
|
||
|
|
|
||
|
|
This program is distributed in the hope that it will be useful,
|
||
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public
|
||
|
|
License along with this program; if not, see
|
||
|
|
<https://www.gnu.org/licenses/>.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
|
||
|
|
means there is a real alloca function. */
|
||
|
|
#ifndef _GL_ALLOCA_H
|
||
|
|
#define _GL_ALLOCA_H
|
||
|
|
|
||
|
|
/* alloca (N) returns a pointer to N bytes of memory
|
||
|
|
allocated on the stack, which will last until the function returns.
|
||
|
|
Use of alloca should be avoided:
|
||
|
|
- inside arguments of function calls - undefined behaviour,
|
||
|
|
- in inline functions - the allocation may actually last until the
|
||
|
|
calling function returns,
|
||
|
|
- for huge N (say, N >= 65536) - you never know how large (or small)
|
||
|
|
the stack is, and when the stack cannot fulfill the memory allocation
|
||
|
|
request, the program just crashes.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef alloca
|
||
|
|
/* Some version of mingw have an <alloca.h> that causes trouble when
|
||
|
|
included after 'alloca' gets defined as a macro. As a workaround,
|
||
|
|
include this <alloca.h> first and define 'alloca' as a macro afterwards
|
||
|
|
if needed. */
|
||
|
|
# if defined __GNUC__ && (defined _WIN32 && ! defined __CYGWIN__) && @HAVE_ALLOCA_H@
|
||
|
|
# include_next <alloca.h>
|
||
|
|
# endif
|
||
|
|
#endif
|
||
|
|
#ifndef alloca
|
||
|
|
# if defined __GNUC__ || (__clang_major__ >= 4)
|
||
|
|
# define alloca __builtin_alloca
|
||
|
|
# elif defined _AIX
|
||
|
|
# define alloca __alloca
|
||
|
|
# elif defined _MSC_VER
|
||
|
|
# include <malloc.h>
|
||
|
|
# define alloca _alloca
|
||
|
|
# elif defined __DECC && defined __VMS
|
||
|
|
# define alloca __ALLOCA
|
||
|
|
# elif defined __TANDEM && defined _TNS_E_TARGET
|
||
|
|
# ifdef __cplusplus
|
||
|
|
extern "C"
|
||
|
|
# endif
|
||
|
|
void *_alloca (unsigned short);
|
||
|
|
# pragma intrinsic (_alloca)
|
||
|
|
# define alloca _alloca
|
||
|
|
# elif defined __MVS__
|
||
|
|
# include <stdlib.h>
|
||
|
|
# else
|
||
|
|
# include <stddef.h>
|
||
|
|
# ifdef __cplusplus
|
||
|
|
extern "C"
|
||
|
|
# endif
|
||
|
|
void *alloca (size_t);
|
||
|
|
# endif
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* _GL_ALLOCA_H */
|