diff --git a/sbin/ifconfig/af_inet.c b/sbin/ifconfig/af_inet.c
--- a/sbin/ifconfig/af_inet.c
+++ b/sbin/ifconfig/af_inet.c
@@ -382,7 +382,7 @@
 #endif
 
 static void
-warn_nomask(ifflags)
+warn_nomask(int ifflags)
 {
     if ((ifflags & (IFF_POINTOPOINT | IFF_LOOPBACK)) == 0) {
 	warnx("WARNING: setting interface address without mask "