unsigned ctl_net_is_multicast_ip_address(CTL_NET_IPv4_ADDR_t addr);
ctl_net_is_multicast_ip_address determines whether addr is an IP multicast address. ctl_net_is_multicast_ip_address returns non-zero if addr is known to be a multicast address zero if not.
ctl_net_is_multicast_ip_address is thread-safe.