diff --git a/include/ebtables_u.h b/include/ebtables_u.h
index dc922dc..8fbaed0 100644
--- a/include/ebtables_u.h
+++ b/include/ebtables_u.h
@@ -230,6 +230,8 @@
 extern struct ebt_u_watcher *ebt_watchers;
 extern struct ebt_u_target *ebt_targets;
 
+extern int use_lockfd;
+
 void ebt_register_table(struct ebt_u_table *);
 void ebt_register_match(struct ebt_u_match *);
 void ebt_register_watcher(struct ebt_u_watcher *);