diff --git a/lib/if.c b/lib/if.c
index 4ba973a..ecf9ff9 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -444,7 +444,7 @@
 
 /* Interface printing for all interface. */
 void
-if_dump_all ()
+if_dump_all (void)
 {
   struct listnode *node;
   void *p;