C Socket GroupChat

A lightweight multi-client TCP chat application built from scratch in C, using raw BSD sockets and POSIX threads (pthreads). It demonstrates low-level network programming concepts including socket creation, binding, listening, accepting connections, and concurrent client handling.

Features

• TCP server that accepts multiple simultaneous client connections
• Thread-per-client architecture: each connected client is handled on its own detached pthread
• TCP client with a simple CLI: type a message and hit Enter to broadcast it
• Basic message framing over the TCP stream

How it works

• The server creates a listening socket and spawns a dedicated thread to accept incoming connections.
• Each accepted connection is handed off to its own thread, which listens for incoming data and prints it.
• Clients connect via connect(), send their username once, then stream chat messages line by line.

Tech stack

• Language: C
• Networking: POSIX sockets (socket, bind, listen, accept, connect, send, recv)
• Concurrency: POSIX threads (pthread_create, pthread_detach)

Build & Run

# Server
gcc SocketServer.c -o SocketServer -lpthread
./SocketServer

# Client
gcc Client.c -o Client -lpthread
./Client

Roadmap / Next steps

• Broadcast messages to all connected clients (currently server-side only)
• Migrate from thread-per-client to select()/poll() for scalability
• Message framing/delimiting for reliable parsing over TCP streams
• IPv6 support

Author

Built as part of a self-taught journey into systems & network programming in C.