Subject: Re: [Boost-maint] Status of Boost.CMT libraries
From: Marshall Clow (mclow.lists_at_[hidden])
Date: 2016-11-30 13:39:21
On Wed, Nov 30, 2016 at 10:18 AM, Andrey Semashev <andrey.semashev_at_[hidden]
> On 11/30/16 21:02, Marshall Clow wrote:
>> On Wed, Nov 30, 2016 at 9:15 AM, Andrey Semashev <
>>> https://github.com/boostorg/date_time/pull/29 -- switch +/- on parsing.
>>>> Definitely correct, will break code.
>>> I think we should fix bugs even if it breaks code. We could try to make
>>> less painful though.
>> I'm really reluctant to make this change. I see it breaking lots of
>> people's code for a small benefit.
>> Short synopsis:
>> There are two ways to describe a timezone difference from GMT (only two?
>> You must be mad! - Ok, two in this instance).
>> * Going west is negative. This reflects the fact that the time "gets
>> earlier" as you go west. In this scheme, San Diego is GMT-8, or "8 hours
>> behind GMT". When it's 8 AM in San Diego, then it's 4 PM in London. This
>> what the ISO specifies. In my experience, this is what I see when people
>> want to use time zones.
>> * Going west is positive. This reflects the "amount of time that needs to
>> be added to the local time to get to GMT. In this scheme, San Diego is
>> GMT+8. This is what Posix specifies.
>> Boost.DateTime has a call named posix_time_zone
Yes, you're correct - my internal auto-correct misfired.
> but it implements ISO time zone semantics.
>> I asked Jeff Garland about this a while back, and he was horrified at the
>> idea of breaking everyone's code for this. His response was "Change the
>> docs, don't break code"
> Thing is, the function have POSIX in its name, so POSIX semantics is
Agreed. But people seem to have dealt with this inconsistency already
(for more than a decade)
> Maybe we should create a new function and deprecate to_posix_string? The
> new function could take an argument to select the desired behavior.
That could work.
I just don't want to break the existing users.
(I suspect there are many)
Boost-Maint list run by bdawes at acm dot org