Doh! I realize now I was working from an older version of the library (I was working with http://www.unitedsoft.ch/boost/boost_timer_2007_30_4.tgz Now I'm working with http://unitedsoft.ch/boost/boost_timer_2007_05_01.zip Is this still the latest? I see the timeGetTime implementation has been improved with timeBeginPeriod and timeEndPeriod. And I see that best_timer had been added which is in line with my previous requests. Thanks. The header for gpt_device has a small documentation bug. //! The gtt_device class is based on GetThreadTimes() to compute the time class gpt_device Philippe Vaucher wrote:
Also the QueryPerformanceCounter device uses millisecond resolution internally. I've adjusted it for microsecond resolution locally.
Hum I didn't understand what you meant by that.
Sorry I'll be more specific. QueryPerformanceCounter has around 10 microsecond accuracy on most systems IIRC. I'm personally using it to time code where the total code must take less than 23 ms so to narrow things down it helps to have microsecond resolution. The qpc_device currently does m_frequency.QuadPart /= 1000 in its constructor and adds to elapsed by doing: m_elapsed += posix_time::milliseconds(milliseconds); I changed it to do m_frequency.QuadPart /= 1000000 in its constructor and add to elapsed by doing: m_elapsed += posix_time::microseconds(microseconds); In terms of what to do when QueryPerformanceCounter leaps I would probably use the GetTickCount value silently so the class just works (tm). I'd probably edit the file locally to assert in debug in that case just for personal curiosity. There was one more problem with QueryPerformanceCounter on some laptops including my old one. When the cpu lowered its clock speed to save battery power the frequency of the timer changed despite the documentation for QueryPerformanceFrequency explicitly saying the frequency cannot change while the system is running. I don't have the laptop anymore so I doubt we'll be able to make and test a fix. Hopefully this isn't common. Thanks, Michael Marcin