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  setvirtualsize                                                        WNDWC
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  Function       Sets the dimensions for the virtual screen of virtual
                 windows.
  Syntax         void setvirtualsize( unsigned char rows,
                                      unsigned char cols );
  Remarks        This optional function sets the rows-by-columns dimensions
                 for a virtual screen.  Keep in mind that two additional rows
                 will be internally added for titles if borders are used.
                 The default at startup is the CRT screen size.
  Return value   None.
  Restrictions   Maximum buffer size is 64k.
  Example        To set the size for a virtual screen with 80 columns and a
                 maximum number of rows:

                   setvirtualsize( 253, 80 );

                 The resulting size would be (253+2)*80*2 = 40,800 bytes
                 which is under 64k.  Rows 254 and 255 would be reserved for
                 top and bottom titles on the border.