IDirectDraw7::FlipToGDISurface method (ddraw.h)
Makes the surface that the GDI writes to the primary surface.
If the method succeeds, the return value is DD_OK.
If it fails, the method can return one of the following error values:
You can call FlipToGDISurface at the end of a page-flipping application to ensure that the display memory that the GDI writes to is visible.
You can also use FlipToGDISurface to make the GDI surface the primary surface so that normal windows, such as dialog boxes, can be displayed in full-screen mode. The hardware must have the DDCAPS2_CANRENDERWINDOWED capability.
FlipToGDISurface disables stereo autoflipping.