1 /* 2 * Copyright Andrey Semashev 2007 - 2015. 3 * Distributed under the Boost Software License, Version 1.0. 4 * (See accompanying file LICENSE_1_0.txt or copy at 5 * http://www.boost.org/LICENSE_1_0.txt) 6 */ 7 /*! 8 * \file timer.hpp 9 * \author Andrey Semashev 10 * \date 02.12.2007 11 * 12 * The header contains implementation of a stop watch attribute. 13 */ 14 15 #ifndef BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_ 16 #define BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_ 17 18 #include <boost/log/detail/config.hpp> 19 #include <boost/log/attributes/attribute.hpp> 20 #include <boost/log/attributes/attribute_cast.hpp> 21 #include <boost/log/attributes/time_traits.hpp> 22 #include <boost/log/detail/header.hpp> 23 24 #ifdef BOOST_HAS_PRAGMA_ONCE 25 #pragma once 26 #endif 27 28 namespace boost { 29 30 BOOST_LOG_OPEN_NAMESPACE 31 32 namespace attributes { 33 34 /*! 35 * \brief A class of an attribute that makes an attribute value of the time interval since construction 36 * 37 * The timer attribute calculates the time passed since its construction and returns it on value acquisition. 38 * The attribute value type is <tt>boost::posix_time::time_duration</tt>. 39 * 40 * On Windows platform there are two implementations of the attribute. The default one is more precise but 41 * a bit slower. This version uses <tt>QueryPerformanceFrequence</tt>/<tt>QueryPerformanceCounter</tt> API 42 * to calculate elapsed time. 43 * 44 * There are known problems with these functions when used with some CPUs, notably AMD Athlon with 45 * Cool'n'Quiet technology enabled. See the following links for more information and possible resolutions: 46 * 47 * http://support.microsoft.com/?scid=kb;en-us;895980 48 * http://support.microsoft.com/?id=896256 49 * 50 * In case if none of these solutions apply, you are free to define <tt>BOOST_LOG_NO_QUERY_PERFORMANCE_COUNTER</tt> macro to 51 * fall back to another implementation based on Boost.DateTime. 52 */ 53 class BOOST_LOG_API timer : 54 public attribute 55 { 56 public: 57 //! Attribute value type 58 typedef utc_time_traits::time_type::time_duration_type value_type; 59 60 private: 61 //! Factory implementation 62 class BOOST_SYMBOL_VISIBLE impl; 63 64 public: 65 /*! 66 * Constructor. Starts time counting. 67 */ 68 timer(); 69 /*! 70 * Constructor for casting support 71 */ 72 explicit timer(cast_source const& source); 73 }; 74 75 } // namespace attributes 76 77 BOOST_LOG_CLOSE_NAMESPACE // namespace log 78 79 } // namespace boost 80 81 #include <boost/log/detail/footer.hpp> 82 83 #endif // BOOST_LOG_ATTRIBUTES_TIMER_HPP_INCLUDED_ 84