[Python-Dev] (time) PEP 418 glossary V2

Steven D'Aprano steve at pearwood.info
Wed Apr 25 19:20:10 CEST 2012

Stephen J. Turnbull wrote:
> On Wed, Apr 25, 2012 at 1:19 AM, Jim Jewett <jimjjewett at gmail.com> wrote:
>> I'm still a little fuzzy on *why* it shouldn't count as a monotonic
>> clock.
> So are the people who say it shouldn't count (unless you're speaking
> of the specific implementation on Unix systems, which can go backward
> if the admin or NTP decides it should be so).

The fact that the clock is not monotonic is a pretty good reason for it not to 
count as monotonic. I don't think there's anything fuzzy about that.

> I think they are in
> general mistaking their use case for a general specification, that's
> all.

I'm sorry, am I missing something here? What use case are you talking about?

> Even Glyph cited "what other people seem to think" in supporting
> the usage where "monotonic" implies "high quality" in some informal
> sense, although he does have a spec for what high quality means, and
> AIUI an API for it in Twisted.

Who are these people who think monotonic is a synonym for "high quality"?

Why should we pander to their confusion at the cost of those who do understand 
the difference between monotonic and high quality?

> I think we should just accept that "monotonic" is in more or less
> common use as a synonym for "high quality", and warn *our* users that
> the implementers of such clocks may be working to a different spec.  I
> think the revised glossary's description of "monotonic" does that
> pretty well.

Do I understand correctly that you think it is acceptable to call something 
monotonic regardless of whether or not it actually is monotonic?

If not, I'm not sure I understand what you are suggesting here.


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