You just need to declspec(dllexport) the classes, with the caveat that thanks to the lack of standard ABI you need the same compiler on both sides.
Then again, most other platforms never were too C++ friendly and rather lean on C.
BeOS, Symbian, Genode and Windows are probably the only OSes that give C++ some love.
You just need to declspec(dllexport) the classes, with the caveat that thanks to the lack of standard ABI you need the same compiler on both sides.