Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   timer.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   02.12.2007
Chris@16:  *
Chris@16:  * The header contains implementation of a stop watch attribute.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/attributes/attribute.hpp>
Chris@16: #include <boost/log/attributes/attribute_cast.hpp>
Chris@16: #include <boost/log/attributes/time_traits.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace attributes {
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief A class of an attribute that makes an attribute value of the time interval since construction
Chris@16:  *
Chris@16:  * The timer attribute calculates the time passed since its construction and returns it on value acquisition.
Chris@16:  * The attribute value type is <tt>boost::posix_time::time_duration</tt>.
Chris@16:  *
Chris@16:  * On Windows platform there are two implementations of the attribute. The default one is more precise but
Chris@16:  * a bit slower. This version uses <tt>QueryPerformanceFrequence</tt>/<tt>QueryPerformanceCounter</tt> API
Chris@16:  * to calculate elapsed time.
Chris@16:  *
Chris@16:  * There are known problems with these functions when used with some CPUs, notably AMD Athlon with
Chris@16:  * Cool'n'Quiet technology enabled. See the following links for more information and possible resolutions:
Chris@16:  *
Chris@16:  * http://support.microsoft.com/?scid=kb;en-us;895980
Chris@16:  * http://support.microsoft.com/?id=896256
Chris@16:  *
Chris@16:  * In case if none of these solutions apply, you are free to define <tt>BOOST_LOG_NO_QUERY_PERFORMANCE_COUNTER</tt> macro to
Chris@16:  * fall back to another implementation based on Boost.DateTime.
Chris@16:  */
Chris@16: class BOOST_LOG_API timer :
Chris@16:     public attribute
Chris@16: {
Chris@16: public:
Chris@16:     //! Attribute value type
Chris@16:     typedef utc_time_traits::time_type::time_duration_type value_type;
Chris@16: 
Chris@16: private:
Chris@16:     //! Factory implementation
Chris@16:     class BOOST_SYMBOL_VISIBLE impl;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Constructor. Starts time counting.
Chris@16:      */
Chris@16:     timer();
Chris@16:     /*!
Chris@16:      * Constructor for casting support
Chris@16:      */
Chris@16:     explicit timer(cast_source const& source);
Chris@16: };
Chris@16: 
Chris@16: } // namespace attributes
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_