Open Source C Messaging Platforms for Mac

See https://pidgin.im/about/ for more information. Pidgin is an instant messaging program which lets you log in to accounts on multiple chat networks simultaneously. It runs on Windows, Linux, and other UNIX operating systems. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, MXit, Novell GroupWise Messenger, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It is written in C and makes heavy use of GLib and GTK+. Finch is a command line instant messaging program. It also lets you log in to accounts on multiple chat network simultaneously, and it is compatible with the same chat networks as Pidgin. It is written in C and makes heavy use of GLib and ncurses.

The gSOAP toolkit is an extensive suite of portable C and C++ software to develop XML Web services with powerful type-safe XML data bindings. Easy-to-use code-generator tools allow you to directly integrate XML data in C and C++. Serializes native application data in XML. Includes WSDL/XSD schema binding and auto-coding tools, stub/skeleton compiler, Web server integration with Apache module and IIS extension, high-performance XML processing with schema validation, fast MIME/MTOM streaming, SOAP and REST Web API development, WS-* protocols (WS-Security, WS-Policy, WS-ReliableMessaging, etc), XML-RPC and JSON. Licensed under GPLv2. Visit the developer center with guides, tutorials, and examples at www.genivia.com/dev.html The documentation of the toolkit, libraries, plugins and more is available at www.genivia.com/docs.html Commercial-use licenses and expert technical support services are available at competitive pricing levels, please visit www.genivia.com/products.html

Tox is a peer to peer (serverless) instant messenger that focuses on security and privacy. In today's world where digital surveillance is rampant, Tox offers users a communication software alternative that's free from prying eyes and ears, and is, quite literally free and without advertising. Tox comes with all the great features you'd expect from an instant messenger application, including voice calls, video calls, file sharing and screen sharing. Everything done on Tox is encrypted using open-source libraries so you can be assured of completely private conversations. It also has no central servers that can be raided, shut down, or forced to turn over data. There are no corporate interests, no hidden agendas-- just simple, secure and easy to use messaging.

A very nice MSN compatible messenger application, aMSN Messenger is a multiplatform MSN messenger clone. Works pretty much like its Windows based counterpart. Perfect for keeping in touch with those friends who have not yet seen the light. Works on linux

Toxic is a Tox protocol-based command-line messenger for Linux, offering fully encrypted, decentralized, and serverless instant messaging. It includes features such as text messaging, file transfer, and audio calls—all without requiring user accounts or central servers. Toxic is designed for power users who prefer a minimalist interface, operating entirely within a terminal while delivering strong privacy through the Tox peer-to-peer protocol. It’s lightweight, fast, and ideal for use in low-resource or remote systems.

Fire is a multi-protocol instant messenger client for Mac OS X based on freely available libraries for each service. Currently Fire handles AOL Instant Messenger®, ICQ®, MSN® Messenger, Jabber, limited IRC, Yahoo!®, and Apple Bonjour communications.

It's just another Instant Messenger based on jabber

PlanetaMessenger.org is a Instant Messenger with support to all well known instant messenger networks including ICQ,MSN,AIM,Yahoo! and Jabber through a powerfull plugin engine. PlanetaMessenger.org support multiples look and feels, plugins and profiles.