diff --git a/sys/net/route/nhop_ctl.c b/sys/net/route/nhop_ctl.c
index 0e9a6b8a0a7..4bf7bfb1b41 100644
--- a/sys/net/route/nhop_ctl.c
+++ b/sys/net/route/nhop_ctl.c
@@ -505,7 +505,7 @@ nhop_create_from_nhop(struct rib_head *rnh, const struct nhop_object *nh_orig,
  * Returns pointer to nhop_priv or NULL.
  */
 static struct nhop_priv *
-alloc_nhop_structure()
+alloc_nhop_structure(void)
 {
 	struct nhop_object *nh;
 	struct nhop_priv *nh_priv;