Mail Archives: cygwin/2012/03/28/03:41:11
On Mar 27 23:28, Christian Franke wrote:
> Corinna Vinschen wrote:
> >On Mar 27 20:59, Christian Franke wrote:
> >>>>Sorry, I probably forgot to mention that NtSetTimerResolution
> >>>>returns the same useless actual value than NtQueryTimerResolution.
> >>>>
> >>>>I would suggest:
> >>>>
> >>>> status = NtSetTimerResolution (period, TRUE,&actual);
> >>>> if (!NT_SUCCESS (status))
> >>>> { ... return -1; }
> >>>> - minperiod = actual;
> >>>> + minperiod = period;
> >>>But that's not right. The "actual" value is not useless, but the value
> >>>the resolution has actually been set to.
> >>No, again this is the minimum of all resolutions currently set by
> >>all processes.
> >>
> >>
> >>> The OS just doesn't support
> >>>arbitrary values for the period.
> >>>
> >>Yes - but in 'actual' a smaller value than the value set for the
> >>current process may be returned.
> >Hmpf, ok. Boy is that ugly.
>
> Yes, aka broken by design :-)
>
> There should be a function to query the actual setting for the
> current process only. But there is none.
>
>
> > Is there a chance that actual is bigger
> >than period? In that case we should perhaps set minperiod like this:
> >
> > minperiod = MAX (actual, period);
>
> According to some experiments this can only happen if period <
> finest. In this case NtSetTimerResolution also succeeds and returns
> actual == finest.
Since period < finest can't happen, I set minperiod to period now as
you suggested. But, frankly, this would have been much simpler if
you would have send a patch right from the start ;)
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat
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