As long as the NSTimer firing interval is sufficiently small the NSTimer can be used. If the run loop is stalled for any "significant: time _all_ timers will be inaccurate to some degree. The NSTimer works fine for animation and , e.g., alarm timers and they are consistent across platforms such as Mac Pros, iMacs, iPhones, etc.
On Jul 26, 2010, at 12:12 PM, Kyle Sluder wrote: > On Jul 26, 2010, at 8:32 AM, Charlie Dickman <[email protected]> wrote: > >> Try using an NSTimer with a repeating timeout interval of, say, .001 (or >> anything smaller than your required accuracy), and countdown your time delta >> by the same amount each time the NSTimer fires and when you get to zero >> you'll have what you need. > > NSTimer is not suitable for timekeeping of any significant resolution. > NSTimer works by comparing the current time at the top of the runloop with > the last time the timer was fired. Obviously, this is highly susceptible to > anything that prevents the runloop from running at at least the timer > interval—which on a modern multitasking operating system is quite likely. > > mach_absolute_time is certainly the way to go. The best advice I've seen out > there is to listen for sleep/wake notifications from IOKit and record the > system time there to figure out how much time has elapsed between the two. > > > --Kyle Sluder Charlie Dickman [email protected] _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
