Hi, I was prototyping my engine, but i get an error appears and I don''t know why. I got an engine class in a dll (engine.dll) that is loaded at load time in the main executable (launch.exe) via a .lib file. Now the engine class contains a pointer to an abstract base class called ''rendrv'' and several functions : class ENGINE_API engine { HINSTANCE hdll; rendrv* p; void print(HDC h, int x, int y) { p->print(h, x, y); } void init(); void exit(); }; the idea is that rendrv is an abstract base class to two other interfaces, one for drawing in OpenGL and one in DirectX. class GL_API glrendrv : public rendrv { public: virtual void print(HDC h, int x, int y) { char str[] = "glrendrv output"; TextOut(h, x, y, str, strlen(str)); } } now the init function loads explicitly the glrendrv dll and casts it''s rendrv pointer to a glrendrv pointer. now in my launch code, i have the following engine e; e.init(); e.print(HDC, 0, 0); e.exit(); now when e.print is called i get an exception : access violation. can anibody tell me what is wrong, or is it impossible for a class member function in a load time dll, to load dynamicly a class at run time from a dll?