event

    OpenVMS usage:event_code
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Event code indicating the type of system 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 $SYSEVTDEF macro defines
    the following symbolic names:

    Symbolic Name               Description

    SYSEVT$C_ADD_MEMBER         One or more OpenVMS instances have
                                joined the OpenVMS Galaxy sharing
                                community.
    SYSEVT$C_DEL_MEMBER         One or more OpenVMS instances have
                                left the OpenVMS Galaxy sharing
                                community.
    SYSEVT$C_ADD_ACTIVE_CPU     One or more processors have become
                                active within this OpenVMS instance.
    SYSEVT$C_DEL_ ACTIVE_CPU    One or more processors have become
                                inactive within this OpenVMS
                                instance.
    SYSEVT$C_ADD_CONFIG_CPU     One or more CPUs have been added to
                                the set of available CPUs for this
                                OpenVMS instance.
    SYSEVT$C_DEL_CONFIG_CPU     One or more processors have been
                                removed from this OpenVMS instance.
    SYSEVT$C_TDF_CHANGE         The system's time differential factor
                                has changed.
    SYSEVT$C_CPU_DEALLOCATE     One or more processors have been
                                deallocated from this OpenVMS
                                instance.

 astadr

    OpenVMS usage:ast_procedure
    type:         procedure value
    access:       call without stack unwinding
    mechanism:    by 32-bit or 64-bit reference
    Notification AST routine to receive control after a change in
    OpenVMS system configuration occurs.

 astprm

    OpenVMS usage:user_arg
    type:         quadword
    access:       read only
    mechanism:    by value
    The quadword AST parameter to be passed to the AST routine.

 acmode

    OpenVMS usage:access_mode
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Access mode at which the system 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.

    Symbolic Name      Description

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

    The value of the access mode is maximized with the access mode of
    the caller.

 flags

    type:
    access:
    mechanism:    0
    Defined in SYSEVTDEF.

    SYSEVT$M_REPEAT_       When this flag is set, event notification
    NOTIFY                 is repeated.

 handle

    OpenVMS usage:handle
    type:         quadword (unsigned)
    access:       read/write
    mechanism:    by reference
    The virtual address of a naturally aligned quadword for the event
    handle.