[tz] Preparing to fork tzdb

[Howard Hinnant]

On Sep 20, 2021, at 7:23 PM, Watson Ladd <watson at cloudflare.com> wrote:
> 
> On Mon, Sep 20, 2021 at 9:51 AM Howard Hinnant via tz <tz at iana.org> wrote:
>> 
>> The C++20 standard has adopted the IANA timezone database (not the code) as the basis for a major part of its API:  http://eel.is/c++draft/time.zone#general-1
>> 
>> I plea for stability.  That doesn’t mean no changes.  But it does mean no drastic changes.
> 
> Unfortunately you are held hostage to the wishes of British Canadian
> chicken farmers, Indiana counties, etc, etc. in determining what the
> zones will be.

Adding new zones is not problematic.  Removing or changing the names of existing ones is.

> The set of zones may increase due to post-1970 changes
> in ways that we cannot predict. And the C++20 standard thankfully does
> not include the list of zones in the API.

A C++20 programmer can easily obtain the list of time zone names and link names from the already standardized API:

    #include <chrono>
    #include <iostream>

    int
    main()
    {
        for (auto& tz : std::chrono::get_tzdb().zones)
            std::cout << tz.name() << '\n';
        for (auto& link : std::chrono::get_tzdb().links)
            std::cout << link.name() << '\n';
    }

Current output:

    Africa/Abidjan
    Africa/Accra
    Africa/Algiers
    Africa/Bissau
    ...


Howard

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: Message signed with OpenPGP
URL: <http://mm.icann.org/pipermail/tz/attachments/20210920/000731e0/attachment.sig>