Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 26329)
+++ wp-includes/post.php	(working copy)
@@ -3626,10 +3626,10 @@
  *
  * @since 1.5.0
  *
- * @param mixed $page Page object or page ID.
+ * @param int|object $page Page ID or page object. Optional, default is the current page from the loop.
  * @return string|false Page URI, false on error.
  */
-function get_page_uri( $page ) {
+function get_page_uri( $page = null ) {
 	$page = get_post( $page );
 
 	if ( ! $page )