EiffelStudio is an IDE for the Eiffel language (ECMA-367, ISO/IEC 25436). It has: an Eiffel compiler, an Eiffel GUI editor, a refactoring tool, Eiffel analysis tools and Eiffel libraries. Eiffel applies O-O principles and Design by Contract for quality. http://www.eiffel.com
Libiqxmlrpc is C++ object-oriented library that represents an XML-RPC solution for both client and server. It supports HTTP and HTTPS, both single-threaded and multi-threaded computation models on the server side, method interceptors, and other features.
AALib/PyAALib - Asynchronous Action Library Project - The project is a Framework based on Pure Object Oriented Concepts to develop asynchronous communication between threads (thread safety) and external process. Platforms: Windows, MacOSX, Linux,Sola
ObjectHandler - an object repository and API allowing objects to be created, interrogated, shared, and destroyed - enabling an object-oriented environment on procedural platforms such as spreadsheets.
PHPCrypt is an object oriented (OO) PHP5 library that makes using encryption in PHP trivial, it is designed to support multiple encryption libraries and currently comes with support for PHP's mcrypt extension.
pyxser stands for python xml serialization and is a python object to XML serializer that validates every XML deserialization against the pyxser 1.0 XML Schema. pyxser is written entirely in C as a python extension.