diff --git a/book/from_flat_php_to_symfony2.rst b/book/from_flat_php_to_symfony2.rst
index 05986aa5a5a..b2506461189 100644
--- a/book/from_flat_php_to_symfony2.rst
+++ b/book/from_flat_php_to_symfony2.rst
@@ -148,7 +148,7 @@ of the application are isolated in a new file called ``model.php``::
         return $link;
     }
 
-    function close_database_connection($link)
+    function close_database_connection(&$link)
     {
         $link = null;
     }