A non-intrusive enhancement of C++ to add runtime reflection capabilities. [Open source, LGPL]

A high performance C++ application framework which provides many classes needed for real-world application development, emphasing on ease of use, size and stability. [Open Source, LGPL]

A C++ serialization library that provides serialization of objects to and from XML and binary formats. It requires Microsoft Visual Studio 2005 and Boost.

a free C++ class library for Microsoft Windows. All source files of the library and a lot of sample programs are available.

A complete C++ based framework for object-oriented cross-platform programming. [Open Source]

Includes a list of available C++ libraries, both public domain and commercial.

A C++ toolkit which enables developers to created distributed peer to peer solutions using agent engineering.

Platform independent C/C++ library for date and time calendric calculations. (by Hofmann Software Engineering International)

A C++ framework for binary reusable objects, or plugins. It enables exposing and sharing run-time type information for C++ classes. [Open Source, BSD]

A C++ based library, that can be used to make programs using functions as in VB. The library has 25 classes ranging from GUI, Threads, String, Active-X. Simple way to convert VB code to C++. [Open source, Qt Public License (QPL)]