[time-nuts] June 30 2015 leap second

Chuck Harris cfharris at erols.com
Wed Jan 7 10:34:07 EST 2015

I couldn't help noticing that Debian just issued an update
to tzone, so that means Linux systems now know about the
leap second.

-Chuck Harris

Tim Shoppa wrote:
> I'm not sure there's any computer time package that correctly disambiguates
> 23:59:59 vs 23:59:60 in UTC timestamps in a general purpose way. Some
> software simply rejects 23:59:60 UTC as invalid, some will quietly map it
> to 23:59:59 effectively making those two seconds impossible to distinguish.
> There are important systems in the world, those that genuinely have to
> distinguish between those two seconds, that do all timekeeping in TAI or
> GPS timescales instead of UTC. I think the Olsen timezone database/library
> does support TAI. I don't know if the Olsen timzone library supports GPS.
> V.P., since you mention Perl and leap seconds, I'd like to point out that
> there's a very useful Perl library for computing delta times around
> leapsecond jumps:
> http://search.cpan.org/~drolsky/DateTime-1.12/lib/DateTime/LeapSecond.pm
> This particular library is useful if you need to know the correct delta
> time between UTC timestamps but have chosen to ignore the ambiguity problem
> of correctly marking the leapsecond itself.
> The "newest announced leap second" is not in the table of leapseconds built
> into the code yet, but it's a simple matter to add it (cut and paste from
> the IPERS).
> Tim.

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