procedure TMyIBEvents.SyncAlert;
begin
  case FSynchroMethod of
    smSynchronize: TThread.Synchronize(nil, DoSync);
    smWindow: Win32Check(PostMessage(FSynchroObject, FSynchroMessage, WPARAM(Self), 0));
    smThread: Win32Check(PostThreadMessage(FSynchroObject, FSynchroMessage, WPARAM(Self), 0));
    smEvent: Win32Check(SetEvent(FSynchroObject));
  end;
end;

function TEventBlock.GetCatchedEvent(out AEvent: string; out ACount: Cardinal): Boolean;
begin
  AEvent := FCatchedEvents[0];
  ACount := Cardinal(FCatchedEvents.Objects[0]);
  FCatchedEvents.Delete(0);
  Result := FCatchedEvents.Count > 0;
  if not Result then
    QueueEvent;
end;

procedure TEventBlock.QueueEvent;
begin
  FOwner.Database.Call(
    FOwner.GDSLibrary.isc_que_events(
      StatusVector,
      @FOwner.Database.Handle,
      @FID,
      FLen,
      FEvents,
      @EventCallback,
      PVoid(Self)
    ),
    True
  );
end;