handle

    OpenVMS usage:identifier
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by reference
    Identification of the asynchronous system trap (AST) to be
    tested. The handle argument uniquely identifies the request and
    is returned when the $SETCLUEVT service is called.

 acmode

    OpenVMS usage:access_mode
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Access mode for which a configuration event AST is to be
    triggered. The acmode argument is a longword containing the
    access mode.

    Each access mode has a symbolic name. The $PSLDEF macro defines
    the following symbols for the four access modes:

    Symbol         Access Mode

    PSL$C_KERNEL   Kernel
    PSL$C_EXEC     Executive
    PSL$C_SUPER    Supervisor
    PSL$C_USER     User

 event

    OpenVMS usage:event_code
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Event code indicating the type of configuration for which an AST
    is to be triggered.

    Each event type has a symbolic name. The $CLUEVTDEF macro defines
    the following symbolic names:

    Symbolic Name      Description

    CLUEVT$C_ADD       One or more OpenVMS nodes have been added to
                       the OpenVMS Cluster system.
    CLUEVT$C_REMOVE    One or more OpenVMS nodes have been removed
                       from the OpenVMS Cluster system.