C++ IO/Multiplexed TCP Server and POSIX Threads

Question

I must develop a simple C++ command line client/server chat application. This application must provide a basic multiple two-partecipants chat-room implementation. Is it possible to combine IO/Multiplexing (select() syscall) with POSIX threads? I mean I want to create a TCP server which handles multiple clients with select() and when a client wants to chat with another one the servewr creates a separate thread , that uses IO/Multiplexing (select() syscall) , to handle the communication between the two clients. Is this a good idea? How could I do otherwise?

Answer 1

A crude attempt at an architecture...

Structure your application as two sets of threads (a set might be composed of just one thread).

One set minds the TCP connections, each TCP connection is assigned to one of the threads in the set, the thread just runs forever polling the connections assigned to it (incoming messages) and polling a (per-thread) from-logic queue (outgoing messages)

The other set minds the logic/session. Each session is assigned to a specific thread. Each thread just runs forever polling the (per-thread) from-network queue (incoming messages).

The network thread-set, receives messages and post them to the right logic queue [assumes there's a way of mapping connections to internal logic sessions]. It polls its from-logic queue to get the outgoing messages and send them.

The number of network threads is bound, and it does not depend on the number of connections.

The logic thread-set, receives requests from the network in its queue and handles them within a given session state and (perhaps) post back messages to the be sent out (sent out by the network threads)

The number of logic threads is bound, and it does not depend on the number of sessions.