Index: wp-includes/post-formats.php
===================================================================
--- wp-includes/post-formats.php	(revision 23933)
+++ wp-includes/post-formats.php	(working copy)
@@ -11,9 +11,9 @@
  *
  * @since 3.1.0
  *
- * @param int|object $post A post
+ * @param int|object $post Post ID or post object. Optional, default is the current post from the loop.
  *
- * @return mixed The format if successful. False if no format is set. WP_Error if errors.
+ * @return mixed The format if successful, false otherwise.
  */
 function get_post_format( $post = null ) {
 	$post = get_post($post);