Chatnet

Chatnet is a small, IRC-inspired, multi-user chat application written in C++. It consists of a threaded TCP server and a GTK desktop client. Many users can connect to the server at once, while each client participates in one private chat session at a time.

Chatnet server and GTK client running on Linux Mint 17 (2026).

Background

Chatnet began in 2012 as a socket-programming exercise. The first version had a command-line client and server; the graphical client was added to explore GTKmm, POSIX threads, and keeping network work from blocking the GTK event loop. The original design notes are preserved in docs/pseudo_code.

How it works

• The server listens for TCP connections on port 7999 and starts a POSIX thread for each connected client.
• On connection, the server validates the chosen nickname. Nicknames must be unique, 3–16 characters long, and contain only letters and digits.
• The GTK client receives connection events in a background thread and keeps its visible user list in sync as people join or leave.
• Starting a chat checks that the selected user is online and not already in another chat. Messages are then relayed privately through the server.
• The client displays server messages and errors in a scrolling log and provides menu and toolbar actions for connecting and disconnecting.

Requirements

Chatnet is a legacy Linux application and uses:

• a C++ compiler and make
• Autoconf, Automake, and pkg-config
• POSIX sockets and threads
• GTKmm 2.4 development files (gtkmm-2.4 via pkg-config)

GTKmm 2.4 is obsolete and may not be available in current distribution repositories. A compatible legacy system or container may therefore be the easiest environment in which to build the GUI.

Build

Generate the configuration script after cloning the repository (release archives may already include it):

autoreconf --install

Configure and build both the server and graphical client from the repository root:

./configure
make

configure checks for a working C++ compiler, POSIX networking headers, POSIX threads, pkg-config, and GTKmm 2.4 before generating the unified root Makefile. The resulting executables are chatnets and chatnetgui in the repository root.

To remove compiled files, run make clean. To remove those files and all generated configuration output, run make distclean.

Install both programs, the desktop launcher, icons, and documentation with:

sudo make install

Installation refreshes both the hicolor icon cache and desktop application database automatically. These are freedesktop.org conventions supported by major Linux desktop environments; the launcher is not tied to a particular distribution or desktop. If an existing session cached an older installation, use that desktop's application-menu refresh mechanism or sign out and back in.

The default installation prefix is /usr/local; select another prefix while configuring, for example ./configure --prefix="$HOME/.local". Use make uninstall to remove files installed by this build.

Run

After make install, start the server first:

chatnets

The server forks into the background and listens on port 7999. Don't panic if there was no output. It's running! and you can verify with netcat.

Then start one or more clients (or start from desktop menu/launcher):

chatnetgui

These commands work without a ./ prefix because make install places the executables in the configured binary directory (/usr/local/bin by default), which is normally included in the user's PATH. If you selected a custom prefix, ensure its bin directory is in PATH.

To run directly from the source tree without installing, use ./chatnets and ./chatnetgui from the repository root.

In each client, choose File → Connect (or the Connect toolbar button), then enter:

• a unique nickname;
• the server hostname or IP address (localhost when running locally); and
• port 7999.

Select a user from the user list to begin a private chat, or enter commands in the message field.

Client commands

Command	Description
/chat <name>	Start a private chat with a connected user.
/endchat	End the current chat session.
/list	Display the connected users.
/clear	Clear the client's message log.
/help	Display the command summary in the client.
/exit	Disconnect from the server.

While a chat is active, text that does not begin with / is sent to the other participant. The protocol also supports /msg <name> :<message> internally, but the GUI normally constructs this command automatically.

Repository layout

configure.ac               Autoconf dependency and platform checks
Makefile.am                Unified server/client build and install rules
server/                    Threaded TCP server
client/chatnetgui/src/     GTKmm client source
client/chatnetgui/icons/   Application icons
client/chatnetgui/desktop/ Desktop launcher
docs/pseudo_code           Original design notes and protocol sketch
docs/chatnet-2026.png      Application screenshot

Project status

This repository is primarily a historical learning project. The code and build system reflect the Linux/C++ ecosystem in which it was originally written, including GTKmm 2.4 and direct POSIX socket/thread APIs.