minitalk — Client-Server Communication via UNIX Signals

42 Urduliz — Common Core project

A minimal client-server communication program that transmits strings bit by bit using only UNIX signals (SIGUSR1 and SIGUSR2).

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How It Works

1. Start the server — it prints its PID
2. Run the client with the server PID and a message string
3. The client encodes each character as 8 bits and sends SIGUSR1 (bit 0) or SIGUSR2 (bit 1) to the server
4. The server reconstructs the characters and prints the message

Build & Run

make
./server &          # prints PID
./client <PID> "Hello, World!"

Technical Highlights

• Pure signal-based IPC — no pipes, no sockets
• Uses sigaction() for reliable signal handling
• Unicode support (multi-byte characters)
• Acknowledgement system: server confirms each character received

Skills

C UNIX Signals IPC Bitwise Operations Linux

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Academic Integrity

This repository is shared for educational and portfolio purposes only.

For 42 students:

• Do not copy this code for your own project submissions
• Use it as a reference to understand concepts and approaches
• Write your own original solution — that is the only way to actually learn

42's core values are learning through practice, peer collaboration, and genuine problem-solving.

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License

MIT — see LICENSE for details. Copyright (c) 2026 Eneko Muñoz Bordona