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From: Jonathan Biggar (jon_at_[hidden])
Date: 2008-05-15 17:16:49

Jeff Garland wrote:
> Jonathan Biggar wrote:
>> I found getting either of thse two bits of information to be much harder
>> than it ought to be:
>> 1. The default time zone for the program.
> Right -- there's not really a portable way to do this unfortunately. So if
> you know a way I'm all ears.
>> 2. The time zone offset for the local_date_time clocks.
> Not sure I understand. You have to pass a tz to the clock as I recall, so how
> does this matter?

Ok, then maybe I'm confused. What's the difference between these two
functions that return ptime?

> ptime second_clock::local_time()
> Get the local time, second level resolution, based on the time zone settings of the computer.
> ptime second_clock::universal_time()
> Get the UTC time.

Isn't second_clock::local_time() - second_clock::universal_time()
theoretically the timezone offset? I'd do that, but there's a chance
that the second_clock ticks between the two calls.

Can't this be calculated by calling localtime() and gmtime() on the same
time_t value and doing the right math? Seems straightforward to me, and
a nice addition to the library.

And once we have the local timezone offset, it shouldn't be too hard to
search the timezone database to fine the zone(s) that match, right?

Jon Biggar
Floorboard Software

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