diff --git a/src/core/dhcp.c b/src/core/dhcp.c
index 5d1395eb..e86060cf 100644
--- a/src/core/dhcp.c
+++ b/src/core/dhcp.c
@@ -102,7 +102,7 @@ static void dhcp_check(struct netif *netif);
 static void dhcp_bind(struct netif *netif);
 #if DHCP_DOES_ARP_CHECK
 static err_t dhcp_decline(struct netif *netif);
-#endif
+#endif /* DHCP_DOES_ARP_CHECK */
 static err_t dhcp_rebind(struct netif *netif);
 static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);