minitalk

A small UNIX signal-based communication program developed as part of the 42 curriculum. minitalk is a small client-server project that sends data between two processes using only SIGUSR1 and SIGUSR2.

It was a good way to build solid foundations in inter-process communication, signal handling, bitwise operations and message reconstruction in C.

Features

• Communication between two processes using UNIX signals
• Client-server architecture
• Character-by-character transmission through bit encoding
• Custom ft_printf integration for formatted output

Project structure

• inc/minitalk.h — main header file
• src/client.c — client program sending a message bit by bit
• src/server.c — server program receiving and reconstructing the message
• src/utils.c — utility functions
• ft_printf/ — local formatted output implementation used by the project
• Makefile — builds the client and server executables

Mandatory part

The mandatory part focuses on the communication flow between the client and the server.

Programs

• server — starts first, prints its PID, then waits for incoming signals
• client — takes a server PID and a string, then sends the message to the server

Core behavior

• the server prints its PID on startup
• the client sends a string to the server using only SIGUSR1 and SIGUSR2
• the server reconstructs each character from incoming bits
• the received message is displayed immediately on the server side

Main components

• client.c — encodes each character into bits and sends them through signals
• server.c — receives signals, rebuilds characters and prints them
• utils.c — provides local utility helpers such as conversions

Build

Build the project:

make

Clean object files:

make clean

Remove object files and executables:

make fclean

Rebuild everything:

make re

Usage

Start the server first:

./server

Then run the client with the server PID and a message:

./client <PID> "Hello from client"

Learning outcomes

This project was my first real introduction to signal-based inter-process communication in C. It helped build solid foundations in:

• UNIX signal handling
• client-server communication patterns
• bitwise encoding and decoding
• asynchronous message reconstruction
• process identifiers and signaling
• modular program organization