EGA43()
 Switches to the 43-line EGA mode
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 Syntax

     EGA43() --> lSwitched

 Returns

     EGA43() returns .T. if the screen graphics adapter successfully switched
     to the 43-line mode.

 Description

     This function can be used with either an EGA or VGA card.  A 43-line
     mode is requested, and the maximum number of coordinates for the
     CA-Clipper screen output is automatically increased.  It isn't necessary
     to also call the SETMAXROW() and SETMAXCOL() functions.

 Note

     Important!  This function cannot be implemented when windows are
     open.

 Example

     The following example switches to 43-line mode, making lines 0 to 42
     available:

     IF ISEGA()
        EGA43()
     ENDIF

     @ 42, 10 SAY "CA-Clipper"      // Last line
     WAIT
     CGA80()                        // Return to 25-line mode