diff --git a/usr.bin/netstat/netstat.h b/usr.bin/netstat/netstat.h
index c24954766e86..5ae8c7f46ece 100644
--- a/usr.bin/netstat/netstat.h
+++ b/usr.bin/netstat/netstat.h
@@ -94,7 +94,7 @@ void	impstats __P((u_long, u_long));
 
 void	intpr __P((int, u_long, void (*) __P((char *))));
 
-void	pr_rthdr __P(());
+void	pr_rthdr __P((int));
 void	pr_family __P((int));
 void	rt_stats __P((u_long));
 char	*ipx_pnet __P((struct sockaddr *));