Hi, I had a similar problem in getting the current wall time in New York. I wrote the following working function and added a bunch of comments, since the library is counter-intuitive here IMHO: // Get local time of day, based on time zone const boost::posix_time::time_duration DateTime::localizedTimeOfDayAsDuration(const boost::local_time::time_zone_ptr timeZone) { /* This looks a bit perverted (and it is in my eyes :-)) Calling time_of_day on a local_date_time object implicitly turns it into a UTC ptime object first, thus yielding UTC time_of_day instead of the wall time (I do not really understand why it works this way, but it does). Calling local_time on a local_date_time object returns a ptime object which in this case represents wall time within the given time zone (again, I don't know why the behavior is this way, but it is). */ return local_microsec_clock::local_time(timeZone).local_time().time_of_day(); } Please let me know if that helped or if you found a better solution/explanation. Regards, Roland Jean-Pierre Bergamin wrote:
Hello
I'm confused about the returned time of the dst_local_start_time() function. First of all I don't understand why a ptime is returned and not a local_date_time, buy anyway.
The ptime I get returned for the timezone Europe/Zurich for 2007 is: 2007-Mar-25 02:00:00 Assuming that this is a UTC time, the local time in Zurich would then be 2007-Mar-25 04:00:00 (because during summertime, Zurich is 2h ahead of UTC), but the correct local dst start time would be 2007-Mar-25 03:00:00 (because the clocks are shifted from 2 to 3). To correctly calculate the dst start time, I have to add the dst_offset to the returned time_of_day.
The returned ptime 2007-Mar-25 02:00:00 seems to be the endtime of wintertime as a local time.
time_zone_ptr zh_tz = tz_db.time_zone_from_region("Europe/Zurich"); ptime zh_dst_start_time = zh_tz->dst_local_start_time(2007); std::cout << zh_dst_start_time << std::endl; // 2007-Mar-25 02:00:00 local_date_time zh_dst_local_start_time = local_date_time(zh_dst_start_time, zh_tz); std::cout << zh_dst_local_start_time << std::endl; // 2007-Mar-25 04:00:00 CEST which is wrong!
ptime zh_dst_start_time_ok = zh_dst_start_time + zh_tz->dst_offset(); local_date_time zh_dst_local_start_time_ok = local_date_time(zh_dst_start_time_ok.date(), zh_dst_start_time_ok.time_of_day(), zh_tz, true); std::cout << zh_dst_local_start_time_ok << std::endl; // 2007-Mar-25 03:00:00 CEST which is correct
So what time exactly is local_start_time() returning? Is this a bug or am I missing something?
Regards
James _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users