xbmac2h.exe is a tool to create the required .h, .def,  and XppRegisterTable entries to export Xbase++ functions in a DLL from  C++ sources without the "_" decoration in function names. Also have special commands to put at Xbase++ level C/C++ macros and symbols avoiding name conflicts.

You can see a sample of input file in the ot4xb package:  ot4xb.mac and the resulting output files: ot4xb.def , ot4xbCpp.def , ot4xb_xbfunclist.hpp and ot4xb_xbexports.hpp