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boost::log::attributes::timer — A class of an attribute that makes an attribute value of the time interval since construction.
// In header: <boost/log/attributes/timer.hpp> class timer : public attribute { public: // types typedef utc_time_traits::time_type time_type; // Time type. // construct/copy/destruct timer(); // public member functions shared_ptr< attribute_value > get_value(); };
The timer attribute calculates the time passed since its construction and returns it on value acquision. The attribute value type is boost::posix_time::time_duration.
On Windows platform there are two implementations of the attribute. The default one is more precise but a bit slower. This version uses QueryPerformanceFrequence/QueryPerformanceCounter API to calculate elapsed time.
There are known problems with these functions when used with some CPUs, notably AMD Athlon with Cool'n'Quiet technology enabled. See the following links for for more information and possible resolutions:
http://support.microsoft.com/?scid=kb;en-us;895980 http://support.microsoft.com/?id=896256
In case if none of these solutions apply, you are free to define BOOST_LOG_NO_QUERY_PERFORMANCE_COUNTER macro to fall back to another implementation based on Boost.DateTime.
timer public member functionsshared_ptr< attribute_value > get_value();
| Returns: | The actual attribute value. It shall not return NULL (exceptions shall be used to indicate errors). |