The Trigger an Event routine causes the event's state to become
    occurred. You control whether all pending actions for the event
    are processed (made to occur), or just one is processed. A
    pending action can be an AST, a signal (condition), or a wakeup.

    Format

      PPL$TRIGGER_EVENT  event-id [,event-param] [,flags]

1  –  Arguments

 event-id

    OpenVMS usage identifier
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Identifier of the event. The event-id argument is the address of
    an unsigned longword containing the identifier.

    Event-id is returned by PPL$CREATE_EVENT.

 event-param

    OpenVMS usage user_arg
    type          longword (unsigned)
    access        read only
    mechanism     by value
    An arbitrary value to be passed to all requests processed for
    the event as a result of the trigger, or, if there are no queued
    event notification requests for this event, to the first caller
    to enable event notification. The event-param argument is the
    address of an unsigned longword containing this value. The value
    of event-param is received by the output argument of PPL$AWAIT_
    EVENT.

    If a participant enables delivery of an AST by calling
    PPL$ENABLE_EVENT_AST, this argument appears in the second
    longword of the vector specified by the astprm argument. If a
    participant enables delivery of a signal by calling PPL$ENABLE_
    EVENT_SIGNAL, this argument appears as the third longword in the
    signal vector when the condition is raised.

 flags

    OpenVMS usage mask_longword
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Specifies options for triggering an event. The flags argument is
    the address of a longword bit mask containing the flag. The valid
    value for flags is as follows:

    PPL$M_NOTIFY_ONE   Processes exactly one enabled event
                       notification. By default, all pending actions
                       are processed when the event state becomes
                       occurred.