The IDirectDraw2::FlipToGDISurface method makes the surface that GDI writes to the primary surface.
HRESULT FlipToGDISurface();
If the method succeeds, the return value is DD_OK.
If the method fails, the return value may be one of the following error values:
| DDERR_INVALIDOBJECT |
| DDERR_INVALIDPARAMS |
| DDERR_NOTFOUND |
This method can be called at the end of a page-flipping application to ensure that the display memory that GDI is writing to is visible to the user.