usr/src/lib/libc/port/gen/posix_memalign.c

   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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "lint.h"
  30 #include <stdlib.h>
  31 #include <errno.h>
  32
  33 /*
  34  * SUSv3 - aligned memory allocation
  35  *
  36  * From the SUSv3 specification:
  37  *    The value of alignment shall be a power
  38  *    of two multiple of sizeof (void *).
  39  * This is enforced below.
  40  *
  41  * From the SUSv3 specification:
  42  *    If the size of the space requested is 0, the behavior
  43  *    is implementation-defined; the value returned in memptr
  44  *    shall be either a null pointer or a unique pointer.
  45  * We choose always to return a null pointer in this case.
  46  * (Not all implementations of memalign() behave this way.)
  47  */
  48 int
  49 posix_memalign(void **memptr, size_t alignment, size_t size)
  50 {
  51         void *ptr = NULL;
  52         int error = 0;
  53
  54         if (alignment == 0 ||
  55             (alignment & (sizeof (void *) - 1)) != 0 ||
  56             (alignment & (alignment - 1)) != 0)
  57                 error = EINVAL;
  58         else if (size != 0 &&
  59             (ptr = memalign(alignment, size)) == NULL)
  60                 error = ENOMEM;
  61
  62         *memptr = ptr;
  63         return (error);
  64 }