This is rather off-topic for this list, but I know that some developers here have a warped interest in this sort of thing. Dataquay is a free open source library that provides a friendly C++ API for the popular Redland RDF data store using Qt4 classes and containers. http://breakfastquay.com/dataquay/ Dataquay is intended to be simple to use and easy to integrate. It is principally intended for use in Qt-based applications that would like to use an RDF datastore as backing for in-memory project data -- that is, data being edited by the user, such as points and their properties in a graphical editor -- to avoid having to provide application data-specific file I/O and to make it easy to augment the data with descriptive metadata pulled in from external sources. Dataquay is also intended to be useful for applications whose primary purpose is not related to RDF but that have ad-hoc RDF needs for metadata management. Dataquay is similar in concept to the Soprano library (http://soprano.sourceforge.net/), but smaller, less sophisticated, and with BSD rather than LGPL licensing. Please see the website for more information, downloads, and caveats. Chris