Function UpdateLayeredWindow 

pub unsafe extern "C" fn UpdateLayeredWindow(
    hWnd: HWND,
    hdcDst: HDC,
    pptDst: *mut POINT,
    psize: *mut SIZE,
    hdcSrc: HDC,
    pptSrc: *mut POINT,
    crKey: COLORREF,
    pblend: *mut BLENDFUNCTION,
    dwFlags: DWORD,
) -> BOOL