diff --git a/docs/reference/glib/tmpl/threads.sgml b/docs/reference/glib/tmpl/threads.sgml
index 6ec1352ed..e3c61fcda 100644
--- a/docs/reference/glib/tmpl/threads.sgml
+++ b/docs/reference/glib/tmpl/threads.sgml
@@ -1613,8 +1613,9 @@ Any one-time initialization function must have its own unique <structname>GOnce<
 struct.
 </para>
 
-@status: 
-@retval: 
+@status: the status of the function controled by this struct
+@retval: the return value of the function controled by this struct. This field will be
+         %NULL unless <literal>status == G_ONCE_STATUS_READY</literal>.
 @Since: 2.4
 
 <!-- ##### ENUM GOnceStatus ##### -->