diff --git a/appl/xnlock/xnlock.c b/appl/xnlock/xnlock.c
index 988959b8d..95c2cf418 100644
--- a/appl/xnlock/xnlock.c
+++ b/appl/xnlock/xnlock.c
@@ -233,7 +233,7 @@ ScreenSaver(save)
 
 /* XXX */
 static void talk(int force_erase);
-static unsigned long look();
+static unsigned long look(void);
 
 
 static void