On Jul 25, 2013, at 11:37 PM, [email protected] wrote: > On Jul 26, 2013, at 12:09 PM, Ken Thomases <[email protected]> wrote: > >> Also, the above code doesn't adjust the timer to fire on the second as Rick >> suggested. You're asking it to fire every so many seconds (delayInSeconds) >> but you aren't specifying when during the second to fire. Rather than >> passing 0 as the second parameter of dispatch_walltime(), you should compute >> an adjustment to try to get close to a whole second. Since >> dispatch_walltime() uses gettimeofday() when you pass NULL for the first >> parameter, I'd use that same call to fill in a timeval structure and then >> pass NSEC_PER_SEC - (tp.tv_usec * NSEC_PER_USEC) as the second parameter. >> >> Regards, >> Ken >> > Thanks Ken, no I hadn't yet bothered to do this, as dispatch_walltime() was > initially close enough to work on the other bits of the app. > It would make a difference to reduce some lag. > What is the part in the second parameter your are doing there… >> NSEC_PER_SEC - (tp.tv_usec * NSEC_PER_USEC) > Looks like something to adust it but what is tp.tv_usec ?
I hypothesized a struct timeval variable named "tp" that you passed to gettimeofday(). Then you would use the sub-second part (the tv_usec field) to figure out roughly how far off of a whole second dispatch_walltime() would be when passed NULL for the first parameter, since it will also use gettimeofday(). Regards, Ken _______________________________________________ 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
