wn_dmode -- set window display mode

        USAGE

          wn_dmode(mode)
          int mode

                  mode = PAINT for painted windows
                  mode = FLASH for instant windows

          wn_dmode sets the windows display mode as per mode, PAINT style
          windows appear to be painted (top to bottom) where FLASH style
          windows instantly appear.

        RETURNS

          Nothing.

        CAUTIONS

          CGA only. Updates are made directly to video memory.