diff --git a/src/undo.c b/src/undo.c
index 1abd41d..0ad3ae1 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -79,7 +79,8 @@
 static int	undo_undoes = FALSE;
 
 /*
- * save the current line for both the "u" and "U" command
+ * Save the current line for both the "u" and "U" command.
+ * Returns OK or FAIL.
  */
     int
 u_save_cursor()