Boost 1.65 log formatter warnings - Visual Studio 2017

[John Coffey]

Andrey, I just downloaded the latest release of Boost 1.65 and I noticed that I am getting a warning on the log formatter somewhere in the template expansion. My visual studio warning level is set to 4. I have my compilation set to treat warnings as errors, and although I could work around this by making an exception to ignore warnign level 4244, I would prefer to not have to do this (as was the case in version 1.64). Is there some static_cast I can add to work around this - can you tell me what changed. It appears that the TimeDurationT template parameter passed to decompose_time_of_day contains hours, minutes and seconds getters that return uint32_t values instead of uint64_t. I am building a 64 bit app.

Thanks in advance

John

The way I call the logger is as follows:

/*static*/
void
Logger::init(const std::map<std::string, fs::path>& rLogInfo)
{
    // Construct the sink for the "event" channel
    for (const auto& rNext : rLogInfo) {
        // empty path=>syslog entry
        if (!rNext.first.empty()) {
            if (!rNext.second.empty()) {
                static const auto gFormatter = expr::format("%1% [%2%] tid[%3%] %4%")
                    % expr::format_date_time<boost::posix_time::ptime>("TimeStamp", "%H:%M:%S.%f")
                    % logging::trivial::severity
                    % expr::attr<attrs::current_thread_id::value_type>("ThreadID")
                    % expr::smessage;
                using text_sink = sinks::synchronous_sink<sinks::text_ostream_backend>;
                auto sink = boost::make_shared<text_sink>();
                sink->locked_backend()->auto_flush(true);
                sink->locked_backend()->add_stream(
                    boost::make_shared<std::ofstream>(
                        rNext.second.c_str()));
                sink->set_formatter(gFormatter);
                sink->set_filter(expr::attr<std::string>("Channel") == rNext.first);
                logging::core::get()->add_sink(std::move(sink));
            } else { // syslog entry - time-stamp not required
                static const auto gFormatter = expr::format("[%1%] tid[%2%] %3%")
                    % logging::trivial::severity
                    % expr::attr<attrs::current_thread_id::value_type>("ThreadID")
                    % expr::smessage;
                using sink_t = sinks::synchronous_sink<sinks::syslog_backend>;
                // Create a new backend
#if defined (_WIN32)
                auto backend = boost::make_shared<sinks::syslog_backend>(
                    keywords::use_impl = sinks::syslog::udp_socket_based,
                    keywords::facility = sinks::syslog::local7);
                backend->set_target_address("localhost", 514);
#else
                // Create a backend
                auto backend = boost::make_shared<sinks::syslog_backend>(
                    keywords::use_impl = sinks::syslog::native,
                    keywords::facility = sinks::syslog::local7);
#endif
                // We'll have to map our custom levels to the syslog levels
                sinks::syslog::custom_severity_mapping<trivial::severity_level> mapping("Severity");
                mapping[trivial::debug] = sinks::syslog::debug;
                mapping[trivial::info] = sinks::syslog::info;
                mapping[trivial::warning] = sinks::syslog::warning;
                mapping[trivial::error] = sinks::syslog::error;
                mapping[trivial::fatal] = sinks::syslog::critical;
                backend->set_severity_mapper(mapping);

                // Wrap it into the frontend and register in the core.
                auto sink = boost::make_shared<sink_t>(backend);
                sink->set_formatter(gFormatter);
                sink->set_filter(expr::attr<std::string>("Channel") == rNext.first);
                logging::core::get()->add_sink(std::move(sink));
            }
        }
    }
    // register common attributes - ThreadID, LineID, TimeStamp etc.
    logging::add_common_attributes();
}

The error details are as follows:

3>Logger.cpp
1>cmdline.vcxproj -> C:\main\dlmu\dlf-0339.1\win32\cmdline\x64\Debug\cmdline.lib
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(66): warning C4244: '=': conversion from '__int64' to 'uint32_t', possible loss of data
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(109): note: see reference to function template instantiation 'void boost::log::v2s_mt_nt6::expressions::aux::date_time_support::decompose_time_of_day<boost::posix_time::time_duration,boost::posix_time::ptime>(const TimeDurationT &,boost::log::v2s_mt_nt6::aux::decomposed_time_wrapper<boost::posix_time::ptime> &)' being compiled
3>        with
3>        [
3>            TimeDurationT=boost::posix_time::time_duration
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(166): note: see reference to function template instantiation 'void boost::log::v2s_mt_nt6::expressions::aux::date_time_support::decompose_time<boost::posix_time::ptime,boost::posix_time::ptime>(const TimeT &,boost::log::v2s_mt_nt6::aux::decomposed_time_wrapper<boost::posix_time::ptime> &)' being compiled
3>        with
3>        [
3>            TimeT=boost::posix_time::ptime
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(156): note: while compiling class template member function 'void boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>::formatter::operator ()(boost::log::v2s_mt_nt6::basic_formatting_ostream<CharT,std::char_traits<char>,std::allocator<char>> &,const boost::posix_time::ptime &) const'
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\detail\light_function.hpp(362): note: see reference to function template instantiation 'void boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>::formatter::operator ()(boost::log::v2s_mt_nt6::basic_formatting_ostream<CharT,std::char_traits<char>,std::allocator<char>> &,const boost::posix_time::ptime &) const' being compiled
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(175): note: see reference to class template instantiation 'boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>::formatter' being compiled
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(174): note: while compiling class template member function 'boost::log::v2s_mt_nt6::aux::light_function<void (boost::log::v2s_mt_nt6::basic_formatting_ostream<char,std::char_traits<char>,std::allocator<char>> &,const boost::posix_time::ptime &)> boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>::parse(const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &)'
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\expressions\formatters\date_time.hpp(96): note: see reference to function template instantiation 'boost::log::v2s_mt_nt6::aux::light_function<void (boost::log::v2s_mt_nt6::basic_formatting_ostream<char,std::char_traits<char>,std::allocator<char>> &,const boost::posix_time::ptime &)> boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>::parse(const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &)' being compiled
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(185): note: see reference to class template instantiation 'boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits_impl<boost::posix_time::ptime,CharT>' being compiled
3>        with
3>        [
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\expressions\formatters\date_time.hpp(96): note: see reference to class template instantiation 'boost::log::v2s_mt_nt6::expressions::aux::date_time_formatter_generator_traits<boost::posix_time::ptime,char,void>' being compiled
3>c:\main\extlibs\boost_1_65_0\boost\log\expressions\formatters\date_time.hpp(95): note: while compiling class template member function 'boost::log::v2s_mt_nt6::expressions::format_date_time_terminal<T,FallbackPolicyT,CharT>::format_date_time_terminal(const boost::log::v2s_mt_nt6::attribute_name &,const boost::log::v2s_mt_nt6::fallback_to_none &,const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &)'
3>        with
3>        [
3>            T=boost::posix_time::ptime,
3>            FallbackPolicyT=boost::log::v2s_mt_nt6::fallback_to_none,
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\expressions\formatters\date_time.hpp(231): note: see reference to function template instantiation 'boost::log::v2s_mt_nt6::expressions::format_date_time_terminal<T,FallbackPolicyT,CharT>::format_date_time_terminal(const boost::log::v2s_mt_nt6::attribute_name &,const boost::log::v2s_mt_nt6::fallback_to_none &,const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &)' being compiled
3>        with
3>        [
3>            T=boost::posix_time::ptime,
3>            FallbackPolicyT=boost::log::v2s_mt_nt6::fallback_to_none,
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\mpl\aux_\preprocessed\plain\or.hpp(51): note: see reference to class template instantiation 'boost::log::v2s_mt_nt6::expressions::format_date_time_terminal<T,FallbackPolicyT,CharT>' being compiled
3>        with
3>        [
3>            T=boost::posix_time::ptime,
3>            FallbackPolicyT=boost::log::v2s_mt_nt6::fallback_to_none,
3>            CharT=char
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\phoenix\core\actor.hpp(199): note: see reference to class template instantiation 'boost::mpl::or_<boost::phoenix::is_custom_terminal<Expr,void>,boost::mpl::bool_<false>,boost::mpl::false_,boost::mpl::false_,boost::mpl::false_>' being compiled
3>        with
3>        [
3>            Expr=boost::log::v2s_mt_nt6::expressions::format_date_time_terminal<boost::posix_time::ptime,boost::log::v2s_mt_nt6::fallback_to_none,char>
3>        ]
3>c:\main\extlibs\boost_1_65_0\boost\log\expressions\formatters\date_time.hpp(154): note: see reference to class template instantiation 'boost::phoenix::actor<boost::log::v2s_mt_nt6::expressions::format_date_time_terminal<T,FallbackPolicyT,CharT>>' being compiled
3>        with
3>        [
3>            T=boost::posix_time::ptime,
3>            FallbackPolicyT=boost::log::v2s_mt_nt6::fallback_to_none,
3>            CharT=char
3>        ]
3>c:\main\dlmu\dlf-0339.1\src\util\logger.cpp(118): note: see reference to class template instantiation 'boost::log::v2s_mt_nt6::expressions::format_date_time_actor<boost::posix_time::ptime,boost::log::v2s_mt_nt6::fallback_to_none,char,boost::phoenix::actor>' being compiled
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(67): warning C4244: '=': conversion from '__int64' to 'uint32_t', possible loss of data
3>c:\main\extlibs\boost_1_65_0\boost\log\support\date_time.hpp(68): warning C4244: '=': conversion from '__int64' to 'uint32_t', possible loss of data
3>util.vcxproj -> C:\main\dlmu\dlf-0339.1\win32\util\x64\Debug\util.lib
3>Done building project "util.vcxproj".

[Andrey Semashev]

Is there some static_cast I can add to work around this - can you tell me what changed.

There was no change in Boost.Log but there might have been a change in Boost.DateTime or some other code or the compiler. Anyway, you will have to either disable the warning or add static_casts to uint32_t in boost/log/support/date_time.hpp in the various decompose_ functions, where there is assignment to decomposed_time_wrapper members.