usr/src/head/alloca.h

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 *
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef	_ALLOCA_H
#define	_ALLOCA_H

#include <sys/types.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Many compilation systems depend upon the use of special functions
 * built into the the compilation system to handle variable argument
 * lists and stack allocations.  The method to obtain this in SunOS
 * is to define the feature test macro "__BUILTIN_VA_ARG_INCR" which
 * enables the following special built-in functions:
 *	__builtin_alloca
 *	__builtin_va_alist
 *	__builtin_va_arg_incr
 * It is intended that the compilation system define this feature test
 * macro, not the user of the system.
 *
 * The tests on the processor type are to provide a transitional period
 * for existing compilation systems, and may be removed in a future
 * release.
 */

#if defined(__BUILTIN_VA_ARG_INCR) || \
	defined(__sparc) || defined(__i386) || defined(__amd64)
#define	alloca(x)	__builtin_alloca(x)

extern void *__builtin_alloca(size_t);

#else

extern void *alloca(size_t);

#endif	/* defined(__BUILTIN_VA_ARG_INCR) || defined(__sparc) ... */

#ifdef __cplusplus
}
#endif

#endif	/* _ALLOCA_H */