boost::corosio::socket_option::leave_group

class leave_group;

void
stop_receiving_an_ipv4_multicast_group(corosio::udp_socket& sock)
{
    // Precondition: sock is open on family::v4 and joined this group.
    //
    // Membership otherwise lasts until the socket closes. The group and the
    // interface have to match the join_group that established it --
    // attempting to leave a (group, interface) pair the kernel has no
    // membership for fails with EADDRNOTAVAIL, which set_option reports by
    // throwing.
    sock.set_option(
        corosio::socket_option::leave_group(
            corosio::ipv4_address("239.255.0.1")));
}