ISANSI()
 Tests to see if the ANSI screen driver is installed
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 Syntax

     ISANSI() --> lInstalledDriver

 Returns

     ISANSI() returns .T. when ANSI.SYS or a comparable driver has been
     loaded from CONFIG.SYS.

 Description

     ISANSI() determines if ANSI.SYS or another comparable driver has been
     loaded from CONFIG.SYS.  Some full-page displays require the ANSI
     driver.  If the driver is present, the display is fully operational.

 Note

     Warning!  You must implement DSETWINDOW(.F.) for ISANSI() to return
     a correct result.

 Example

     If ANSI.SYS is present, output through DOS.  This allows a simple
     terminal emulation:

     IF ISANSI()                  // ANSI driver present?
        COM_DOSCON(dDate)         // Output via DOS
     ELSE
        *...                      // Individual ANSI handling
     ENDIF