[LEAPSECS] Time math libraries, UTC to TAI

[John Sauter]

On Tue, 2016-12-27 at 12:34 +0000, Robert Jones wrote:
> 
> As a minor note, the SQL standard requires timestamps to be in the 
> format (simplified to ignore timezones, variable precisions, etc) 
> yyyymmddhhmmss.ssssss where it is currently for the implementor to 
> decide how to do the date and time manipulations.
> 
> SQL 2008 standard
> 
> 4.6.2 Datetimes (extracts)
> 
> — TIMESTAMP — contains the <primary datetime field>s YEAR, MONTH,
> DAY, 
> HOUR, MINUTE, and
> SECOND
> 
> A datetime value, of data type TIME WITHOUT TIME ZONE or TIMESTAMP 
> WITHOUT TIME ZONE,
> may represent a local time, whereas a datetime value of data type
> TIME 
> WITH TIME ZONE or TIMESTAMP
> WITH TIME ZONE represents UTC.
> 
> in the SQL 2008 standard see NOTE 101 — Datetime data types will
> allow 
> dates in the Gregorian format to be stored in the date range
> 0001–01–01 
> CE through
> 9999–12–31 CE. The range for SECOND allows for as many as two “leap 
> seconds”. Interval arithmetic that involves leap seconds
> or discontinuities in calendars will produce implementation-defined
> results.
> 
> Robert

"Produce implementation-defined results" is a cop-out, considering that
there is a leap second every few years.  If we can fix the software so
that leap seconds are routinely handled correctly, the standard can
remove that last sentence.
    John Sauter (John_Sauter at systemeyescomputerstore.com)

-- 
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