[systemd-devel] [PATCH] timedated: Add a LocalOffset property for timezone offset

[David Herrmann]

Hi

On Mon, Mar 23, 2015 at 6:32 AM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Thu, 19.03.15 14:39, David Herrmann (dh.herrmann at gmail.com) wrote:
>
>> Hmm, so this is a convenience call. You could just set tm.tm_zone
>> locally and use mktime() with the value retrieved by "Timezone"? Yeah,
>> the time-api is awful with global variables, but that's not really our
>> fault, is it?
>
> This would not work, as struct tm's .tm_zone field is not sufficient
> to indicate a timezone. The code would have to set $TZ and call tzset().

I see. The Unix-way of doing things!

> Given the simplicity of this I'd probably just merge Stef's
> patch... It *is* kinda nice given that the timezone database is
> constantly updated and having this exposed on the bus so that it is
> accessible remotely has the benefit that you get the actual timezone
> information in effect on the remote system, and not a possible
> out-of-date timezone from the local database. If you follow what I mean...

..locale data is also updated regularly but we don't export
locale-files on the bus ;)

Anyway, if we add pseudo-redundant APIs, I'd go with a "LocalTime"
field as Shawn suggested. This is what the bus-user is interested in,
right? If they need more data (like DST), they should just parse
zoneinfo. And with "LocalTime" we avoid any ambiguity regarding DST.

Thanks
David