event

    OpenVMS usage:event_code
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Event code indicating the type of cluster configuration event for
    which an AST is to be delivered. The event argument is a value
    indicating which type of event is of interest.

    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.

 astadr

    OpenVMS usage:ast_procedure
    type:         procedure value
    access:       call without stack unwinding
    mechanism:    by reference
    Notification AST routine to receive control after a change in
    OpenVMS Cluster configuration occurs.

 astprm

    OpenVMS usage:user_arg
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Optional AST parameter to be passed to the AST service routine.
    The astprm argument is a longword value containing the AST
    parameter.

 acmode

    OpenVMS usage:access_mode
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Optional access mode at which the configuration event AST is to
    execute. 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

    The value of the access mode must not be more privileged than the
    access mode of the caller.

 handle

    OpenVMS usage:identifier
    type:         quadword (unsigned)
    access:       write only
    mechanism:    by reference
    Optional identifier to receive a value that uniquely identifies
    this AST request. $SETCLUEVT sets this handle to a unique value
    so that it can later be used to identify the request in the
    $CLRCLUEVT and $TSTCLUEVT services.