xref: /illumos-gate/usr/src/lib/libc/port/gen/posix_memalign.c (revision 1edba515a3484e0f74b638b203d462b3112ac84d)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include "lint.h"
28 
29 #include <sys/sysmacros.h>
30 
31 #include <stdlib.h>
32 #include <errno.h>
33 
34 /*
35  * SUSv3 - aligned memory allocation
36  *
37  * From the SUSv3 specification:
38  *    The value of alignment shall be a power
39  *    of two multiple of sizeof (void *).
40  * This is enforced below.
41  *
42  * From the SUSv3 specification:
43  *    If the size of the space requested is 0, the behavior
44  *    is implementation-defined; the value returned in memptr
45  *    shall be either a null pointer or a unique pointer.
46  * We choose always to return a null pointer in this case.
47  * (Not all implementations of memalign() behave this way.)
48  */
49 int
50 posix_memalign(void **memptr, size_t alignment, size_t size)
51 {
52 	void *ptr = NULL;
53 
54 	if ((alignment == 0) || !ISP2(alignment) ||
55 	    (alignment & (sizeof (void *) - 1)) != 0) {
56 		return (EINVAL);
57 	} else if (size == 0) {
58 		*memptr = NULL;
59 		return (0);
60 	} else {
61 		if ((ptr = memalign(alignment, size)) == NULL) {
62 			return (ENOMEM);
63 		} else {
64 			*memptr = ptr;
65 			return (0);
66 		}
67 	}
68 }
69