Im currently writing a 3D-engine and i want it to be Graphics API-independent so i want to put all the code for graphics-drawning in a DLL. I try to CreateWindow() inside the DLL (i pass pointer to HWND, WndProc etc.) but i get alot of invalid conversion errors. I don''t have my code with me (ill post it tommorow) but are there any good tutorials on the topic? There are alot of information about OpenGL, Windows GDI etc. but i havent seen any on how to do it inside a DLL. Futhermore i found a great tutorial on flipcode.org on how to load objects without .def-files so now i can load entire objects and not just plain C-stuff .