Format options:

       /CLOSURE=keyword
       /NOCLOSURE (default)

    Specifies whether CDO reserves additional elements. A CLOSURE
    operation fails if any element is a child of an element outside
    the area defined by the CLOSURE keyword.

    CLOSURE takes one of the following keywords:

    CLOSURE
    Keyword      Behavior

    TO_BOTH      Reserves the element specified and all owners and
                 members.

    TO_BOTTOM    Reserves the element specified and all members.

    TO_CLOSURE   Reserves the element specified, all owners, and any
                 element under the top collection that depends on the
                 element specified.

    TO_TOP       Reserves the element specified and all owners.

    In most cases, you can specify the TO_BOTH, TO_TOP, or TO_BOTTOM
    keywords. The TO_CLOSURE keyword is useful when you are working
    with the source and derived files common in system building
    applications.

    If you specify TO_BOTH, TO_CLOSURE, or TO_TOP, CDO ignores owners
    of the top collection.