GeoDLL supports 2D and 3D coordinate transformation, geodetic datum shift and reference system convertion, meridian strip changing, user defined coordinate and reference systems, distance calculation, Digital Elevation Model, NTv2 handling, Direct / Inverse Solutions and a lot of other geodetic functions.
The DLL has become very fast and save by forceful development in C++ with Microsoft Visual Studio 2010. The geodetic functions of the new version 12.05 now are available in 32bit and 64bit architecture.
You find a downloadable test version on http://www.killetsoft.de/p_gdla_e.htm.
Fred