Re: [Boost-maint] Status of Boost.CMT libraries

Subject: Re: [Boost-maint] Status of Boost.CMT libraries
From: Paul A. Bristow (pbristow_at_[hidden])
Date: 2016-12-01 05:27:32

> -----Original Message-----
> From: Boost-maint [mailto:boost-maint-bounces_at_[hidden]] On Behalf Of Marshall Clow
> Sent: 30 November 2016 18:39
> To: boost-maint_at_[hidden]
> Subject: Re: [Boost-maint] Status of Boost.CMT libraries
> 
> On Wed, Nov 30, 2016 at 10:18 AM, Andrey Semashev <andrey.semashev_at_[hidden]
> > wrote:
> 
> > On 11/30/16 21:02, Marshall Clow wrote:
> >
> >> On Wed, Nov 30, 2016 at 9:15 AM, Andrey Semashev <
> >> andrey.semashev_at_[hidden]>
> >> wrote:
<snip>
> >> 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
> >> is
> >> 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.
> >> http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html
> >>
> >> Boost.DateTime has a call named posix_time_zone
> >>
> >
> > to_posix_string?
>  
> Yes, you're correct - my internal auto-correct misfired.

:-)
 
> > but it implements ISO time zone semantics.
> > 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)

Two functions sounds the only sensible resolution to me if ISO and Posix differ.

It costs us very little.

to_ISO_string?

Paul

---
Paul A. Bristow
Prizet Farmhouse
Kendal UK LA8 8AB
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