[LEAPSECS] Future time

Gerard Ashton ashtongj at comcast.net
Sun Jan 19 11:07:05 EST 2014


Date/time manipulation software sometimes converts a date expressed as day,
month, year, time to a number, as in Excel. If the number counts leap
seconds, and an event is more than 6 months in the future, it will be
necessary to search for the number using a range rather than an exact
number. For example, if Excel were revised to account for leap seconds, and
one wanted to search for 8 PM January 14, 2015, rather than searching for
42018.8333... one would have to search for something like a time t, where
42018.83332 < t < 42018.83335. This of course overlooks whatever "fuzz"
Excel may silently employ in searches.

Gerard Ashton

-----Original Message-----
From: leapsecs-bounces at leapsecond.com
[mailto:leapsecs-bounces at leapsecond.com] On Behalf Of Daniel R. Tobias
Sent: Sunday, January 19, 2014 10:35 AM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] Future time

On 18 Jan 2014 at 19:51, Warner Losh wrote:


> Of course, the 6 month window does make it impossible to compute a

> time_t for a known interval into the future that's longer than 6 months

away...

What are the applications that actually need to schedule events more than 6
months in the future that need to be precisely synchronized to civil time at
a resolution of under a second? Gee, I might miss the plane for the airline
reservation I made 7 months in advance if I show up one second late!
(Actually, both myself and the airline, if we care about this level of
detail, will have adjusted our clocks/watches by flight day, including any
leap seconds in the interim, and I'll be right on time.)

--
== Dan ==
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