Using a Multiple Document Interface

Applications that use a multiple document interface (MDI) might need to specify window styles that are not available through the MCIWndCreate function. For these applications, you can register and create an MCIWnd window by using the MCIWndRegisterClass function with the CreateWindowEx function. The MCIWndRegisterClass function registers the MCIWND_WINDOW_CLASS window class and then CreateWindowEx creates an instance of an MCIWnd window.