import grlib
    predef grPlot(x, y)#0
    predef grHLin(x1, x2, y)#0
    predef grVLin(y1, y2, x)#0
    predef grBLT(x, y, width, height, src)#0
    predef grTile(x, y, src)#0
    predef grTileStr(x, y, tilestr, strlen, tilebuff)#0
    predef grFill(x, y, tile)#0
    predef dgrVLB#0
    predef grClear(clr)#0
    predef grMode(mode)#1
    predef grShow(page)#1
    predef grSwap#0
    predef grDrawBuf(page)#0
    predef grColor(clr)#0
    const  grPage1 =  0
    const  grPage2 =  1
    const  grOff   = -1
end
