import qualified Graphics.X11.Xlib as Xlib
import Vulkan hiding (allocate)
import Foreign.Ptr (Ptr, WordPtr (..), wordPtrToPtr, castPtr)

castDisplay :: Xlib.Display -> Ptr Display
castDisplay dpy = wordPtrToPtr $ WordPtr (read ((words $ show dpy) !! 1) :: Word)

-- with castPtr
castDisplay2 :: Xlib.Display -> Ptr Display
castDisplay2 (Xlib.Display dpy) = castPtr dpy