10880 posix_memalign() should avoid clobbering return parameter on failure

@@ -22,13 +22,14 @@
 /*
  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident   "%Z%%M% %I%     %E% SMI"
-
 #include "lint.h"
+
+#include <sys/sysmacros.h>
+
 #include <stdlib.h>
 #include <errno.h>
 
 /*
  * SUSv3 - aligned memory allocation

@@ -47,18 +48,21 @@
  */
 int
 posix_memalign(void **memptr, size_t alignment, size_t size)
 {
         void *ptr = NULL;
-        int error = 0;
-
-        if (alignment == 0 ||
-            (alignment & (sizeof (void *) - 1)) != 0 ||
-            (alignment & (alignment - 1)) != 0)
-                error = EINVAL;
-        else if (size != 0 &&
-            (ptr = memalign(alignment, size)) == NULL)
-                error = ENOMEM;
 
+        if ((alignment == 0) || !ISP2(alignment) ||
+            (alignment & (sizeof (void *) - 1)) != 0) {
+                return (EINVAL);
+        } else if (size == 0) {
+                *memptr = NULL;
+                return (0);
+        } else {
+                if ((ptr = memalign(alignment, size)) == NULL) {
+                        return (ENOMEM);
+                } else {
         *memptr = ptr;
-        return (error);
+                        return (0);
+                }
+        }
 }