xref: /illumos-gate/usr/src/head/alloca.h (revision ba3594ba)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
24  *
25  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 #ifndef	_ALLOCA_H
30 #define	_ALLOCA_H
31 
32 #include <sys/types.h>
33 
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37 
38 /*
39  * Many compilation systems depend upon the use of special functions
40  * built into the the compilation system to handle variable argument
41  * lists and stack allocations.  The method to obtain this in SunOS
42  * is to define the feature test macro "__BUILTIN_VA_ARG_INCR" which
43  * enables the following special built-in functions:
44  *	__builtin_alloca
45  *	__builtin_va_alist
46  *	__builtin_va_arg_incr
47  * It is intended that the compilation system define this feature test
48  * macro, not the user of the system.
49  *
50  * The tests on the processor type are to provide a transitional period
51  * for existing compilation systems, and may be removed in a future
52  * release.
53  */
54 
55 #if defined(__BUILTIN_VA_ARG_INCR) || \
56 	defined(__sparc) || defined(__i386) || defined(__amd64)
57 #define	alloca(x)	__builtin_alloca(x)
58 
59 extern void *__builtin_alloca(size_t);
60 
61 #else
62 
63 extern void *alloca(size_t);
64 
65 #endif	/* defined(__BUILTIN_VA_ARG_INCR) || defined(__sparc) ... */
66 
67 #ifdef __cplusplus
68 }
69 #endif
70 
71 #endif	/* _ALLOCA_H */
72