On Mon, 24 Oct 2005, Tom Lane wrote:
> Qingqing Zhou <[EMAIL PROTECTED]> writes: > > I tried to persuade myself that removing all WaitForSingleObjectEx() is > > safe ... the thing is we will false alarm EINTR as Magnus said (details to > > repeat it are list below in case). > > Just to repeat myself: there were false alarms before. The interleaving > you describe could equally well happen if a new signal is sent just > after the old code executes WaitForSingleObjectEx and sees that a > previous signal is waiting for it. Both old and new signals can be > cleared by the recipient before the second signal sender gets as far as > setting the event. > Oh, yeah. Just write the detailed case down for the sake of memory: -- For previous code -- false alarm case -- 1. I am killing you signal A: enter_crit; set signal bit; leave_crit; 2. He *has killed* you signal B: 3. You CHECK_FOR_INTERRUPTS(): enter_crit; sig(A); sig(B); ResetEvent(); leave_crit; 4. I finish my killing: SetEvent(); Now the event is signaled but the signal is handled already. Regards, Qingqing ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
