diff --git a/mod/chat/lib.php b/mod/chat/lib.php
index 73a290f8a45..e6ebbd72a9b 100644
--- a/mod/chat/lib.php
+++ b/mod/chat/lib.php
@@ -141,6 +141,7 @@ function chat_user_outline($course, $user, $mod, $chat) {
 /// $return->time = the time they did it
 /// $return->info = a short text description
 
+    $return = NULL;
     return $return;
 }
 
diff --git a/mod/wiki/lib.php b/mod/wiki/lib.php
index 1a9931788ae..bae402b1982 100644
--- a/mod/wiki/lib.php
+++ b/mod/wiki/lib.php
@@ -169,6 +169,7 @@ function wiki_get_participants($wikiid) {
 //in the instance, independient of his role (student, teacher, admin...)
 //See other modules as example.
 
+    $return = NULL;
     return false;
 }