[tz] Creston

Alan Barrett apb at cequrux.com
Mon Feb 27 16:21:45 UTC 2012

On Mon, 27 Feb 2012, Robert Elz wrote:
>    From:        Alan Barrett <apb at cequrux.com>
>  | I always considered "is DST in effect, and if so, what is the
>  | offset from standard time" to be an important question,
>Could you perhaps explain why?

Partly because I imagine that at least some of the people who live 
in the area would care about it (some government officials, even 
if no ordinary people), and partly because it's exposed in the 
API.  If you call mktime() twice, with tm_isdst=0 and tm_isdst=1, 
and subtract the results, then you get the DST offset; if both 
results are equal, then you know that there is no DST for that 

> Notions of "standard" time vs summer time are purely ones of 
> perception.  For those areas with bi-annual clock jumps, we 
> could just as easily consider the time during summer to be the 
> "standard" time, and that that applies during winter to be 
> "winter adjustment time" applied to allow the sun to rise at 
> an earlier clock time in winter.  It is all just a matter of 
> perception, and I don't really think it important at all.

Well, yes, it's just a matter of perception, but I think the 
database should try to match the perception of the people.

> I'm not going to delay this update to wait for this to be 
> perfected however.

That's very sensible.

--apb (Alan Barrett)

More information about the tz mailing list