diff --git a/share/man/man9/RUN_ONCE.9 b/share/man/man9/RUN_ONCE.9
index 7136f957b53f..5b125bc1ba54 100644
--- a/share/man/man9/RUN_ONCE.9
+++ b/share/man/man9/RUN_ONCE.9
@@ -1,4 +1,4 @@
-.\"	$NetBSD: RUN_ONCE.9,v 1.4 2006/01/16 23:58:43 wiz Exp $
+.\"	$NetBSD: RUN_ONCE.9,v 1.5 2006/01/17 00:14:16 wiz Exp $
 .\"
 .\" Copyright (c)2005 YAMAMOTO Takashi,
 .\" All rights reserved.
@@ -53,6 +53,9 @@ is executed (successfully) exactly once.
 It is considered as a successful execution if and only if
 .Fn init_func
 returned 0.
+As long as there was no successful execution,
+.Fn RUN_ONCE
+will try again each time it is called.
 .Pp
 .Fn RUN_ONCE
 can sleep if it's called concurrently.