[LEAPSECS] USWP7A docs for 2013 September meetings
imp at bsdimp.com
Mon Aug 19 18:41:11 EDT 2013
On Aug 19, 2013, at 4:23 PM, Zefram wrote:
> Warner Losh wrote:
>> That is unless the API explicitly says "always hide leap seconds from
>> users in this way"...
> That's basically what it says. The API is based around a single base
> time scale, which in the present era is UTC-SLS. The only way leap
> seconds would matter for a computation with JSR-310 would be if you
> converted between its time scale and some other time scale such as TAI.
> No such conversion is available through the API, so that doesn't arise.
> Computations within the time scale, which are the main business of the
> API, are unaffected by leap seconds, because they use the seconds of
> UTC-SLS without caring that some of them are of different lengths when
> looked at in a different way.
> The only place where leap seconds directly affect the operation of
> the API is where you ask a Clock object what the current time is.
> It must reply in UTC-SLS, thus hiding leap seconds in the standard way.
> But implementations aren't obliged to provide an accurate clock. If they
> don't advertise that a clock is sub-second accurate, then a POSIX-like
> discontinuity around leap seconds is acceptable, just as it's acceptable
> for the clock to give readings that are minutes off.
By catering to the sucky implementation, it precludes the precision one :(
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