DBSETINDEX()
 Open an index
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 Syntax

     DBSETINDEX(<cIndexName>) --> NIL

 Arguments

     <cIndexName> is a character value that specifies the filename of the
     index file to be opened.

 Returns

     DBSETINDEX() always returns NIL.

 Description

     DBSETINDEX() opens an index file for the current work area.  Any index
     files already associated with the work area continue to be active.  If
     the newly opened index is the only index associated with the work area,
     it becomes the controlling index; otherwise, the controlling order
     remains unchanged.

     After the new index file is opened, the work area is positioned to the
     first logical record in the controlling order.

     DBSETINDEX() performs the same function as the standard SET INDEX
     command or the INDEX clause of the USE command.  For more information,
     refer to the SET INDEX command.

 Notes

     .  Logical records: Activating an index affects the logical order
        of records in the work area.  That is, when an index is active,
        commands which operate on logical records process records in indexed
        order.  If the controlling index is a unique index, records with
        duplicate index keys are not logically visible.

     .  Network environment: DBSETINDEX() opens the index for shared
        access if the associated database file was opened for shared access.
        Otherwise, the index opens for exclusive access.

 Examples

     .  The following example sets multiple indexes:

        cLast := "Winston"
        DBUSEAREA( .T., "DBFNTX", "Sales", "Sales", .T. )
        DBSETINDEX( "FIRSTNAM" )
        DBSETINDEX( "LASTNAME" )
        //
        IF ( Sales->(DBSEEK(cLast)) )
           IF Sales->( DELETED() ) .AND. Sales->( RLOCK() )

              Sales->( DBRECALL() )
              ? "Deleted record has been recalled."
           ENDIF
        ELSE
           ? "Not found"
        ENDIF

 Files:  Library is CLIPPER.LIB.