Re: localtime on native Windows

[Brian.Inglis@systematicsw.ab.ca]

On 2024-02-17 19:14, Bruno Haible wrote:
> Brian Inglis wrote:
>> I was looking around ... that required data can be shrunk to ~300KB using Brotli!?
> 
> Whereas the entire tzdata.zi (without comments, and with abbreviations) is
> only around 100 KB. I'll definitely prefer the latter.
> 
>> Other options would be for some selection of generated data such as using
>> zonenow.tab, supporting only the current time onward
> 
> This is a simplification that one may do when working on an embedded system
> or such. But not in gnulib. When the entire data file is 100 KB, it is not
> a good compromise to give up correctness for dates in the past, in exchange
> for further data size reduction.
> 
>> https://github.com/unicode-org/cldr/blob/main/common/supplemental/windowsZones.xml
> 
> This file is interesting for its mapping table from Windows time zones.

My point was that this data is already built into Windows, and accessible via 
its ICU API, so gnulib does not need to include, update, and compile tzdata to 
support Windows.

It just has to adapt its localization, as does Cygwin, which uses the Windows 
zones to look up tz ids, which it uses to load tzdata to provide POSIX 
interfaces, using otherwise mostly BSD code adapted from tzcode, required by 
newlib to allow commercial and other uses by RedHat and other embedded vendors.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry