If you are working on windows only, and really need a C++ interface, use COM/DCOM. It is based on RPC (in turn based on DCE RPC).
It is extremely simple to use -- provided you take the time to learn the basics.
- ATL: http://msdn.microsoft.com/en-us/library/3ax346b7(VS.71).aspx
- Interface Definition Language: http://msdn.microsoft.com/en-us/library/aa367091(VS.85).aspx
