On Mar 27 20:59, Christian Franke wrote: > Corinna Vinschen wrote: > >On Mar 27 20:01, Christian Franke wrote: > >>Corinna Vinschen wrote: > >>>On Mar 26 19:00, Christian Franke wrote: > >>>>Corinna Vinschen wrote: > >>>>>I see your point, but what bugs me a bit is the fact that > >>>>>clock_getres(CLOCK_REALTIME) and clock_setres(CLOCK_REALTIME) will > >>>>>always return the same value coarsest, regardless what value has been > >>>>>set. > >>>>If clock_setres was called and succeeded, then clock_getres(.) > >>>>should return the value set before. > >>>> > >>>>If clock_setres was not called, the coarsest value is IMO the only > >>>>value that can be guaranteed. > >>>> > >>>>The actual value returned by NtQueryTimerResolution is simply > >>>>useless in this context: It is the minimum of all resolutions > >>>>currently set by all running processes. It may change at any time. > >>>>There is apparently no way the query the current setting of the > >>>>current process. > >>>Uh, right, I misunderstood. I reverted the change to clock_setres. > >>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. Is there a chance that actual is bigger than period? In that case we should perhaps set minperiod like this: minperiod = MAX (actual, period); Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple