SET EXCLUSIVE

    SET EXCLUSIVE determines the way in which database and related memo and
    index files are opened.  It is used in conjunction with multi-user
    environments.

Syntax

    SET EXCLUSIVE ON/OFF

Usage

    When EXCLUSIVE is ON, all database and associated files are opened as
    non-shareable and cannot be USEd by other users until they are CLOSEd.

    When EXCLUSIVE is OFF, all non-shared access must be controlled
    programmatically using RLOCK(), FLOCK(), and USE...EXCLUSIVE.