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     The setvideomode function selects a screen mode appropriate for a
     particular hardware/display configuration. The <mode> argument can
     be one of the symbolic constants shown below and defined in
     FGRAPH.FD.
 
     Note that in OS/2, only text video modes may be selected by
     setvideomode.
 
                Symbolic Constants for Screen Mode
 
     Mode              Type         Size        Colors      Adapter
 
     $DEFAULTMODE      Hardware default mode
     $MAXRESMODE       Highest resolution graphics mode
     $MAXCOLORMODE     Maximum colors graphics mode
     $TEXTBW40         M/T          40x25       16          CGA
     $TEXTC40          C/T          40x25       16          CGA
     $TEXTBW80         M/T          80x25       16          CGA
     $TEXTC80          C/T          80x25       16          CGA
     $MRES4COLOR       C/G          320x200     4           CGA
     $MRESNOCOLOR      M/G          320x200     4           CGA
     $HRESBW           M/G          640x200     2           CGA
     $TEXTMONO         M/T          80x25       1           MA
     $HERCMONO         Hercules     720x348     1           HGC
                       graphics
     $MRES16COLOR      C/G          320x200     16          EGA
     $HRES16COLOR      C/G          640x200     16          EGA
     $ERESNOCOLOR      M/G          640x350     1           EGA
     $ERESCOLOR        C/G          640x350     16          EGA
     $VRES2COLOR       C/G          640x480     2           VGA
     $VRES16COLOR      C/G          640x480     16          VGA
     $MRES256COLOR     C/G          320x200     256         VGA
     $ORESCOLOR        C/G          640x400     1 of 16     Olivetti
                                                            graphics
 
     Type:     M indicates monochrome. C indicates color output. T
               indicates text. G indicates graphics.
 
     Size:     For text modes, size is given in characters (column
               multiplied by rows). For graphics modes, size is given in
               pixels (horizontal multiplied by vertical).
 
     Colors:   For monochrome displays, the number of colors is the
               number of grey shades.
 
     Adapter:  Adapters are the IBM (and compatible) Monochrome Adapter
               (MDPA), Color Graphics Adapter (CGA), Enhanced Graphics
               Adapter (EGA), Video Graphics Array (VGA), Hercules-
               compatible adapter, and Olivetti-compatible adapter.
 
     Note that only standard hardware is described here, but display
     hardware that is strictly compatible with IBM, Hercules, or
     Olivetti hardware should also work as described.
 
     The two special modes $MAXRESMODE and $MAXCOLORMODE select the
     highest resolution and most colorful video mode available with the
     current hardware, respectively. These two modes fail for adapters
     that do not support graphics modes.
 
     Listed below are the video modes selected for different adapter and
     monitor combinations when $MAXRESMODE or $MAXCOLORMODE is
     specified:
 
     Adapter/Monitor     $MAXRESMODE      $MAXCOLORMODE
 
     MDPA                fail             fail
     HGC                 $HERCMONO        $HERCMONO
     CGA color           $HRESBW          $MRES4COLOR
     CGA noncolor        $HRESBW          $MRESNOCOLOR
     OCGA                $ORESCOLOR       $MRES4COLOR
     OEGA color          $ORESCOLOR       $ERESCOLOR
     EGA color 256k      $HRES16COLOR     $HRES16COLOR
     EGA color 64k       $HRES16COLOR     $HRES16COLOR
     EGA ecd 256k        $ERESCOLOR       $ERESCOLOR
     EGA ecd 64k         $ERESCOLOR       $HRES16COLOR
     EGA mono            $ERESNOCOLOR     $ERESNOCOLOR
     MCGA                $VRES2COLOR      $MRES256COLOR
     VGA                 $VRES16COLOR     $MRES256COLOR
     OVGA                $VRES16COLOR     $MRES256COLOR
 
     Note that a color monitor is assumed for CGA adapters if the
     startup text mode was TEXTC80 or TEXTC40. If the initial text mode
     is TEXTBW80 or TEXTBW40, a noncolor CGA monitor is assumed.
 
     Hercules Support
 
     In $HERCMONO mode, only monochrome (two-color) text and graphics
     are supported. The screen resolution is 720 x 348 pixels. The text
     dimensions are 80 columns by 25 rows, with a 9 x 14 character box.
     The bottom two scan lines of the twenty-fifth row are not visible.
 
     You must install the Hercules driver MSHERC.COM before running your
     program. Type MSHERC to load the driver. This can be done from an
     AUTOEXEC.BAT file.
 
     If you have both a Hercules monochrome card and a color video card,
     you should install MSHERC.COM with the /H (/HALF) option. The /H
     option causes the driver to use one instead of two graphics pages.
     This prevents the two video cards from attempting to use the same
     memory. You do not have to use the /H option if you have only a
     Hercules card. See your Hercules hardware manuals for more details
     of compatibility.
 
     To use a mouse, you must follow special instructions for Hercules
     cards in the "Microsoft Mouse Programmer's Reference Guide". (This
     must be ordered separately; it is not supplied with either
     Microsoft C or the mouse package.)
 
     Return Value
 
     The function returns the number of text rows if successful. If an
     error occurs (that is, the mode selected is not supported by the
     current hardware configuration), the function returns 0.
                                    -♦-