ulong get_tcp_port (pushort -w port, p_tcp_server_table servers, p_tcp_point_v4 topic)
{
  records_in (servers->table, servers->length, 
                              (p_tcp_point_v4 ptr) {
                                                     if (ptr->addr->eq (topic->addr)) 
                                                     { 
                                                       *port = ptr->port; break; 
                                                     }
                                                   });
}