Hi,
just to let you know about a rather new project (perhaps I am
the last to see it):
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology
Suite (JTS). As such, it aims to contain the complete functionality of JTS
in C++. This includes all the OpenGIS "Simple Features for SQL" spatial
predicate functions and spatial operators, as well as specific JTS topology
functions such as IsValid().
http://geos.refractions.net
It seems that also those people like topology 
Cheers
Markus