-static inline int multicast4(const struct sockaddr_in *sin) {
- return IN_MULTICAST(ntohl(sin->sin_addr.s_addr));
+/** @brief Return nonzero if @p sin4 is an IPv4 multicast address */
+static inline int multicast4(const struct sockaddr_in *sin4) {
+ return IN_MULTICAST(ntohl(sin4->sin_addr.s_addr));