clarification on kqueue kernel event flags.

Hello,

I got confused with EV_CLEAR flag. Some code follows.

  kev.ident  = 1;
  kev.filter = EVFILT_TIMER;
  kev.flags  = EV_ADD | EV_DISPATCH;
  kev.data   = 4;
  kev.fflags = NOTE_SECONDS;

 l_reg_ev:
  status = kevent(kq, &kev, 1, NULL, 0, NULL);

  for(;;){
   status = kevent(kq, NULL, 0, &kev, 1, NULL);
   kev.flags = EV_ENABLE;
   goto l_reg_ev;
  }

This prints the series of:

id      :  1
> flags   :  EV_DISPATCH EV_CLEAR
> filter  :  EVFILT_TIMER
> data    :  # times timeout has expired since last kevent call: 1
>

The "man kevent", the EV_CLEAR section says that:

> After the event is retrieved by the user, its state is reset.
>

What I expect is that after the first goto, the EV_DISPATCH flag gets
cleared. What does "the state" mean in the above?
More specifically, what exactly EV_CLEAR changes with any combination of
flags and filters?

P.S.
I did read a source code for "/sys/kern/kern_event.c". My brain fails to
understand it as a whole, so, please be easy on me.

-- 
Ярослав Машко

+380 50 56 75 347 <+380+50+56+75+347>