diff --git a/sys/net/if.h b/sys/net/if.h
index 8cc3ba0eec99..8cf713c18c55 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: if.h,v 1.117 2006/06/23 19:02:51 drochner Exp $	*/
+/*	$NetBSD: if.h,v 1.118 2006/06/25 07:50:00 yamt Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2000, 2001 The NetBSD Foundation, Inc.
@@ -294,7 +294,7 @@ struct ifnet {				/* and the entries */
 	void	*if_afdata[AF_MAX];
 	struct	mowner *if_mowner;	/* who owns mbufs for this interface */
 
-	void	*if_agrprivate;
+	void	*if_agrprivate;		/* used only when #if NAGR > 0 */
 };
 #define	if_mtu		if_data.ifi_mtu
 #define	if_type		if_data.ifi_type