BOOLEAN
KeAlertThread(
  IN  PKTHREAD Thread,
  IN  KPROCESSOR_MODE AlertMode
  );

Routine Description:

    This function attempts to alert a thread and cause its execution to
    be continued if it is currently in an alertable Wait state. Otherwise
    it just sets the alerted variable for the specified processor mode.

Arguments:

    Thread  - Supplies a pointer to a dispatcher object of type thread.

    AlertMode - Supplies the processor mode for which the thread is
        to be alerted.

Return Value:

    The previous state of the alerted variable for the specified processor
    mode.