Do you need extra sockets to have 3-way communication?

I have a client/server connection over TCP 开发者_如何学Cusing send() and recv(). This is working in full duplex just fine. However, if I want a 3rd party to be able to join in mid session and communicate on this line, how is it accomplished? Do I need another socket?

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Yes you need a second socket. TCP socket are connection oriented, so they are useful only to manage a single connection beetwen 2 hosts.

Typically you can use a socket open on a well known port to use for establish connection from clients to the server. Then, once the connection has been established, you can transfer it to another socket.

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If you aren't restricted to TCP, IP multicast and other protocols layered on top of it could be an option depending on your application.

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Another option might be to use UDP, which is connectionless. Each datagram will contain the sender. It's up to you, however, to construct a meaningful stream of conversation out of the unordered, unreliable datagrams.