The Return Information About a Zone routine returns formatted
    information about a zone in the 32-bit virtual address space,
    detailing such information as the zone's name, characteristics,
    and areas, and then passes the information to the specified or
    default action routine.

    Format

      LIB$SHOW_VM_ZONE  zone-id [,detail-level]

                        [,user-action-procedure] [,user-arg]