Re: [boost] [datetime] US DST issues

From: Jeff Garland (jeff_at_[hidden])
Date: 2007-02-26 23:46:33

Jody Hagins wrote:
> I understand this topic has been discussed several times, but I am
> unable to find a clear, authoritative indication as to the current
> status of the library.

Sorry to be so slow and difficult about this :-(

> Specifically, I use boost 1.33.1, as released.  What do I have to do in
> order to use Boost.DataTime appropriately in light of the new US DST
> changes?

Unfortunately, the answer is, it depends. There are multiple features in the 
library to help calculate dst -- can you share precisely *how* you are 
calculating dst?

> Currently, my list includes applying the RPM update for glibc to all my
> linux boxes.  Do I need to do anything else?  Earlier emails made me
> think that DateTime uses an independent mechanism for applying timezone
> information.  Is this true?

Yes, it does. If you are using the tz_database you will need to install the 
new version of the 'date_time_zonespec.csv' file.  It's in the vault at:

http://boost-consulting.com/vault/index.php?&direction=0&order=&directory=date_time

Please be aware that when you install this file if you use it to calculate 
times prior to 2007 it will be in error because it does not support historical 
  timezone data.

If you are using the dst_calc_engine or one of the 'deprecated' static 
calculation functions you will need a code update.  I'm putting the final 
changes on these updates now.  Some of the static methods will actually 
support historic times although their interfaces had to change.  I'll try to 
post a summary and patches for 1.33 after I'm done.

> Basically, I want to know what changes I need to make to my programs
> and/or libraries that use Boost.DateTime aside from the glibc update?

glibc won't have an impact on date-time...so you'll have to do something more.

One more little detail. Canada has also changed DST rules to match the new US 
rules.  Mexico did not.  So it's really a North American DST rule update not 
just a US change.

Jeff