_getca -- get character and attribute

        USAGE

          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.

        RETURNS

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

        CAUTIONS

          None.