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emacs/lib/alloca.in.h

64 lines
2.0 KiB
C

/* Memory allocation on the stack.
Copyright (C) 1995, 1999, 2001-2004, 2006-2014 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
<http://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
# ifdef __GNUC__
# 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
# else
# include <stddef.h>
# ifdef __cplusplus
extern "C"
# endif
void *alloca (size_t);
# endif
#endif
#endif /* _GL_ALLOCA_H */