tw_Say( wT, wL, strg, pattr )
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     Display a string at a given screen location. The programmer is
     responsible to ensure output is in bounds. This function uses
     direct screen writes and therefore will not obey Clipper's
     DISPBEGIN(), DISPEND() sequence.

       Arguments:

     wT,wL - 'N' Screen coordinates at which to begin the display.

     strg  - 'A' String to display.

     pattr - 'N' Display colour attribute. Correct numbers may be found
                 with a return from twVAttr( cColour ).

       Return:

     None.

       Example:

     tw_Say( 3, 4, "now is the time", twVAttr( "w+/b" ))