INDEXEXT()
 Return the default index extension based on the database driver currently
 linked
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 Syntax

     INDEXEXT() --> cExtension

 Returns

     Unless you have linked another database driver, INDEXEXT() returns
     ".ntx" to indicate that the default CA-Clipper driver is in effect.  If
     the dBASE III PLUS compatible database driver is linked, the function
     returns ".ndx".

 Description

     INDEXEXT() returns the default index file extension by determining which
     database driver is currently linked. Note that it is preferable to use
     ORDBAGEXT() than INDEXEXT().

 Notes

     .     INDEXEXT() returns the default index extension of the
        driver loaded, not the actual index file extension.  If no driver is
        loaded, ".ntx" is returned.

 Examples

     .  In this example, INDEXEXT() creates an existence test for the
        Customer index file independent of the database driver linked into
        the current program:

        USE Customer NEW
        //
        IF .NOT. FILE("Customer" + INDEXEXT())
           INDEX ON CustName TO Customer
        ENDIF

 Files   Library is CLIPPER.LIB.