!short:_getca
         ^b_getca -- get character and attribute^b

        ^UUSAGE^U

          unsigned int _getca(page, row, col)
          int page, row, col;


                page - video page #
                row -  row value (0-24)
                col -  column value (0-79)

          _getca fetches the character and attribute at the screen 
          coordinates defined by row and column.  _getca is a general 
          purpose routine and can be used outside of the window 
          environment.

        ^URETURNS^U

          The character and attribute as an unsigned int.  The attribute 
          is in the upper byte, the character is in the lower byte.

        ^UCAUTIONS^U

          None.
!short: _putca
         ^b_putca -- put character and attribute ^b

        ^UUSAGE^U

          _putca(page, atch, row, col);
          int page, row, col;
          unsigned atch;

                page - video page #
                atch - attribute and character
                         attribute in high order byte
                         character in low order byte
                row -  row position for character (0-24)
                col -  column position for character (0-79)

          _putch is a general purpose routine that can be used outside of 
          the window environment.

        ^URETURNS^U

          Nothing.

        ^UCAUTIONS^U

          None.
!short: _vidbit
         ^b_vidblt -- video block transfer^b

        ^UUSAGE^U

          _vidblt(sseg, soff, dseg, doff, n);
          unsigned sseg, soff, dseg, doff;
          int n;

                sseg - source segment
                soff - source offset
                dseg - destination segment
                doff - destination offset
                n -    number of bytes to BLT

          _vidblt is similar to the lattice movedata() function except 
          that it waits for the video retrace signal before performing 
          the block transfer.

          _vidblt is a general purpose function that can be used outside 
          of the window environment.

        ^URETURNS^U

          Nothing

        ^UCAUTIONS^U

          For use in color systems only.

          _vidblt references wn_sbit.
