Boost C++ Libraries: Ticket #2718: local_date_time noticeably faster than ptime

Boost C++ Libraries: Ticket #2718: local_date_time noticeably faster than ptime https://svn.boost.org/trac10/ticket/2718 We noticed recently that using a local_date_time in tight loops was several times faster than using a ptime object. As these are both based largerly on the same template code this was a surprise. It appears this is caused by the implementation of the operater+=/-= and was wondering if there was any justification for the difference or if this was just an oversight. <div class="wiki-code"><div class="code"><pre> //.\boost\date_time\local_time\local_date_time.hpp local_date_time_base operator+=(const time_duration_type& td) { this->time_ = time_system_type::add_time_duration(this->time_,td); return *this; } </pre></div></div><div class="wiki-code"><div class="code"><pre> //.\boost\date_time\time.hpp time_type operator+=(const time_duration_type& td) { time_ = (time_system::get_time_rep(date(), time_of_day() + td)); return time_type(time_); } </pre></div></div> It looks like the ptime implementation is doing extra work to split the ptime into date and time_duration components and if it is changed to follow a similar pattern to that used in the local time the performance is then indistinguishable. <div class="wiki-code"><div class="code"><pre> //.\boost\date_time\time.hpp time_type operator+=(const time_duration_type& td) { this->time_ = time_system::add_time_duration(this->time_, td); return time_type(time_); } </pre></div></div> I can only think that maybe this was done to work around an issue and in which case should the same then be applied to the local time implementation? <a class="ext-link" href="http://www.nabble.com/user/SendEmail.jtp?type=user&user=627065">email via nabble</a> en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/2718 Trac 1.4.3