ORDISUNIQUE()
 Return the status of the unique flag for a given order
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 Syntax

     ORDISUNIQUE([<cOrder> | <nPosition>],
        [<cIndexFile>]) --> lUnique

 Arguments

     <cOrder> | <nPosition> is the name of the order or a number
     representing its position in the order list.  Using the order name is
     the preferred method since the position may be difficult to determine
     using multiple-order index files.  If omitted or NIL, the controlling
     order is assumed.

     Specifying an invalid order will raise a runtime error.

     <cIndexFile> is the name of an index file, including an optional
     drive and directory (no extension should be specified).  Use this
     argument with <cOrder> to remove ambiguity when there are two or more
     orders with the same name in different index files.

     If <cIndexFile> is not open by the current process, a runtime error is
     raised.

 Returns

     ORDISUNIQUE() returns the status of the indicated order's unique flag as
     a logical value.

 Description

     By default, this function operates on the currently selected work area.
     It will operate on an unselected work area if you specify it as part of
     an aliased expression.

 Examples

     .  This example shows the return value of ORDISUNIQUE() using
        various orders:

        USE Customer VIA "DBFCDX"
        INDEX ON LastName TAG Last UNIQUE
        INDEX ON FirstName TAG First
        INDEX ON Age TO j:\test\tmp\age UNIQUE

        SET ORDER TO TAG Last

        ? ORDISUNIQUE()                // Result: .T. for Last
        ? ORDISUNIQUE("First")         // Result: .F.
        ? ORDISUNIQUE("Age")           // Result: .T.

 Files   Library is CLIPPER.LIB.