From: Greg Hennessy on
On 2010-07-21, Chris Rebert <clp2(a)rebertia.com> wrote:
> On Tue, Jul 20, 2010 at 6:31 PM, Greg Hennessy <greg.hennessy(a)cox.net> wrote:
>> Given the documentation talks about "double leap seconds" which don't
>> exist, why should this code be trusted?
>
> Because they exist(ed) in POSIX.

Why should POSIX time calculations involving leap seconds be trusted?

This is a pet peeve of mine, when will someone actually implement leap
seconds correctly?

And as a professional astronomer myself, I'm well aware of Steve
Allen's website. :)

From: Chris Rebert on
On Tue, Jul 20, 2010 at 6:48 PM, Greg Hennessy <greg.hennessy(a)cox.net> wrote:
> On 2010-07-21, Chris Rebert <clp2(a)rebertia.com> wrote:
>> On Tue, Jul 20, 2010 at 6:31 PM, Greg Hennessy <greg.hennessy(a)cox.net> wrote:
>>> Given the documentation talks about "double leap seconds" which don't
>>> exist, why should this code be trusted?
>>
>> Because they exist(ed) in POSIX.
>
> Why should POSIX time calculations involving leap seconds be trusted?

I'm not saying they necessarily should, but they're standardized and
the `time` module is based on POSIX/Unix-ish assumptions; not
following POSIX would be inconsistent and problematic.
<Mr.-Mackey-voice>Breaking standards is bad, M'Kay?</Mr.-Mackey-voice>

> This is a pet peeve of mine, when will someone actually implement leap
> seconds correctly?

Well, at least there's the possibility they will be eliminated in the
future anyway, which would make their implementation a non-issue. :-)

Cheers,
Chris
--
http://blog.rebertia.com
From: Steve Allen on
On Jul 20, 6:57 pm, Chris Rebert <c...(a)rebertia.com> wrote:
[regarding trust of POSIX vis a vis leap seconds]
> I'm not saying they necessarily should, but they're standardized and
> the `time` module is based on POSIX/Unix-ish assumptions; not
> following POSIX would be inconsistent and problematic.
> <Mr.-Mackey-voice>Breaking standards is bad, M'Kay?</Mr.-Mackey-voice>

Standards are good. When it comes to leap seconds there can be no
current implementation which satisfies everyone because of this
http://www.ucolick.org/~sla/leapsecs/epochtime.html
Until the delegates to ITU-R SG7 produce a better recommendation there
is going to be chaotic disregard of the standard where folks with
different needs choose different practical implementations.