I think Gennadiy wants the dll code to call a user-defined function, and the problem is that if you declare the function and then leave it undefined the linker complains, even though this works fine with static linking, since the user supplies the definition and the linker sees everything at once.
OK, but would it not be better just to use boost::function<> to allow the user to pass in a user-defined function at run-time from wherever he chooses ? This is much more flexible than attempting to declare a user-defined function in a Dll which the end-user is supposed to define and depend on compile/link to resolve it..
Flexibility point aside this is the way static version is working. I just looking for solution to do the same with dll. As for callback based interface (another thing is that I couldn't depend on boost::function) your proposition would complicate users interface: one need not only define the init function itself but she also has to write main function itself that invoke the framework and pass this callback (or another function I would call from main myself but this would be catch-22) Gennadiy