[Boost-users] [DateTime] from time_t to ptime and back - or not

Subject: [Boost-users] [DateTime] from time_t to ptime and back - or not
From: Christoph Duelli (duelli_at_[hidden])
Date: 2010-08-20 11:23:15

[I am using Boost 1.43.0 on linux, gcc 4.4.1]

I am having trouble with date_time's ptime.
I am passing it a time_t, and store that in a ptime object.
When I retrieve the time_t, I am getting a different value than the one I 
passed to it originally.
(the difference seems to be 2 hours - in all probability due to UTC vs local 
time issues).

Code:
  time_t now = time(NULL);
  boost::posix_time::ptime pt = boost::posix_time::from_time_t(now);
  struct tm tm = to_tm(pt);
  time_t should_be_now = mktime(&tm);
  BOOST_CHECK_EQUAL(now, should_be_now);

fails for me: now is by 7200 seconds (i.e. 2 hours) ahead of.

Is this a bug in date_time or am I just failing to use it properly?

Thank you,
and best regards

Christoph