Boost logo

Boost :

Subject: Re: [boost] [date_time] Time zone improvements
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-05-25 07:15:05

grubino wrote:
> WRT the historical time zone change support, that's actually
> huge for me because without it I cannot use boost::date_time
> without it.

We found it necessary to create a mechanism for managing a reverse chronologically ordered set of time zone rules to account for historical changes. We modified the zone names to include an optional delimiter and effective year which we split to regain the normal zone name and the year which is used as a key to finding the corresponding rule. Thus, we determine the time zone data to apply to a given local_time by determining its year and then looking for the rule that was in effect as of that year.

Even with that logic, we still don't have support for zones with multiple transitions in a given year, such as occur when a state decides to ignore or recognize DST midway through a year or to switch from one time zone to another.

Perhaps we missed something in the provided time zone support that would have obviated our work.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP

IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

Boost list run by bdawes at, gregod at, cpdaniel at, john at