Boost C++ Libraries: Ticket #13463: Boost UDP multicast sender not using correct port

attachment set

anonymous — Sun, 04 Mar 2018 01:12:23 GMT

attachment → UdpMulticastSender_1_66.cpp

anonymous — Sun, 04 Mar 2018 01:15:14 GMT

I have previously tested the unicast UDP time server (http://www.boost.org/doc/libs/1_65_0/doc/html/boost_asio/tutorial/tutdaytime6/src.html) and client (http://www.boost.org/doc/libs/1_65_0/doc/html/boost_asio/tutorial/tutdaytime4/src.html) provided sample codes. They work, and the port specified is correctly observed with Wireshark. Could someone tell me what went wrong with this UDP multicast sender?

nguyen.tnhoang@… — Sun, 04 Mar 2018 01:32:37 GMT

OK, I manage to narrow down the error, but not sure how it happens. In the sender() class constructor:

sender(boost::asio::io_context& io_context, const boost::asio::ip::address& multicast_address)

: endpoint_(multicast_address, multicast_port), socket_(io_context, endpoint_.protocol()), timer_(io_context), message_count_(0)

I change the line:

socket_(io_context, endpoint_.protocol()),

into

socket_(io_context, udp::endpoint(udp::v4(), 13000)),

It works properly. Wireshark shows the packages sent with that specified source port of 13000. However, if I change it to:

socket_(io_context, udp::endpoint(udp::v4(), multicast_port)),

It still won't work, despite multicast_port being specified as 13000. Please help. I need the source port to be dynamically set. Thank you.

anonymous — Sun, 04 Mar 2018 02:41:14 GMT

I change the order of the private members in the code:

private:

unsigned short multicast_port = 13000; 30001 int max_message_count = 10; boost::asio::ip::udp::endpoint endpoint_; boost::asio::ip::udp::socket socket_; boost::asio::steady_timer timer_; int message_count_; std::string message_;

now everything works as intended. Please close the ticket.