[ntp:questions] Leap second to be introduced in June

Harlan Stenn stenn at ntp.org
Fri Jan 23 04:42:59 UTC 2015

Mike S writes:
> Both TAI and UTC are continuous, and could in a non-standard way, be 
> represented by real numbers ("Time," below), where they wouldn't differ. 
> TAI and UTC only differ in how they're "labelled," as you say. It's 
> POSIX which isn't monotonic or continuous, it repeats leap seconds. How 
> they handle leap seconds:
> Time   UTC         TAI         POSIX
> n+0    23:59:58    00:00:33    n+0
> n+1    23:59:59    00:00:34    n+1
> n+2    23:59:60    00:00:35    n+2
> n+2.9  23:59:60.9  00:00:35.9  n+2.9
> n+3    00:00:00    00:00:36    n+2
> n+3.9  00:00:00.9  00:00:36.9  n+2.9
> n+4    00:00:01    00:00:37    n+3

The only problem with this approach is that with this approach under
POSIX, time is discontiguous - one cannot cleanly map from POSIX to UTC
or TAI.

This is some of the fun stuff NTF"s General Timestamp API gets to deal

Harlan Stenn <stenn at ntp.org>
http://networktimefoundation.org - be a member!

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