Method Stdio.UDP()->add_membership()

Method add_membership: int add_membership(string group, void|string address)
Description: Join a multicast group. group contains the address of the multicast group the application wants to join or leave. It must be a valid multicast address. address is the address of the local interface with wich the system should join to the multicast group. If not provided the system will select an appropriate interface. See also the Unix man page for setsocketopt IPPROTO_IP ADD_MEMBERSHIP.
See also: drop_membership