diff --git a/doc/plus4.sgml b/doc/plus4.sgml
index 11468bb33..645de5161 100644
--- a/doc/plus4.sgml
+++ b/doc/plus4.sgml
@@ -121,6 +121,7 @@ declaration and usage.
 <item>cbm_save
 <item>cbm_write
 <item>get_tv
+<item>waitvsync
 </itemize>