message: dont incr reactor->event_num
diff: @@ -321,14 +321,12 @@ static void swKqueueSignal_set(int signo, swSignalHandler handler)
  {
  int fd;
  } *reactor_obj = reactor->object;
  - uint32_t new_event_num;
  // clear signal
  if (handler == NULL)
  {
  signal(signo, SIG_DFL);
  bzero(&signals[signo], sizeof(swSignal));
  EV_SET(&ev, signo, EVFILT_SIGNAL, EV_DELETE, 0, 0, NULL);
  - new_event_num = reactor->event_num <= 0 ? 0 : reactor->event_num - 1;
  }
  // add/update signal
  else
  @@ -336,31 +334,15 @@ static void swKqueueSignal_set(int signo, swSignalHandler handler)
  signal(signo, SIG_IGN);
  signals[signo].handler = handler;
  signals[signo].signo = signo;
  - if (signals[signo].active)
  - {
  - // the event already exists, do not change event_num
  - new_event_num = reactor->event_num;
  - }
  - else
  - {
  signals[signo].active = 1;
  - // otherwise increment event_num
  - new_event_num = reactor->event_num + 1;
  - }
  // save swSignal* as udata
  EV_SET(&ev, signo, EVFILT_SIGNAL, EV_ADD, 0, 0, &signals[signo]);
  }
  int n = kevent(reactor_obj->fd, &ev, 1, NULL, 0, NULL);
  - if (n < 0)
  - {
  - if (sw_unlikely(handler))
  + if (n < 0 && sw_unlikely(handler))
  {
  - swWarn("kevent set signal[%d] error, errno=%d", signo, errno);
  - }
  - return;
  + swSysWarn("kevent set signal[%d] error", signo);
  }
  - // change event_num only when kevent() succeeded
  - reactor->event_num = new_event_num;
  }
  #endif
  