c – 升级log severity_logger init_from_stream

我使用提升日志的severity_logger.
我想从流中配置我的接收器.
(在下面的例子中我使用一个stringstream.
在我的真实应用程序中,流来自一个文件.)
我想使用％Severity％作为输出或过滤目的.

我的问题是：如果我使用它在下面的例子中给出,％Severity％是空的.

％LineID％和％Message％按预期填写.
如果我在附近的线路中设置了一个水槽,它的工作原理如预期.

有任何想法吗？

#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/log/utility/setup/common_attributes.hpp>
#include <boost/log/utility/setup/from_stream.hpp>
#include <boost/log/utility/setup/console.hpp>
#include <boost/log/expressions.hpp>

enum SeverityLevel { trace,fatal };

int main (int argc,char *argv[])
{
    boost::log::add_common_attributes();
    /*
    struct severity_tag;
    boost::log::add_console_log(std::clog,boost::log::keywords::format = (
            boost::log::expressions::stream
                << boost::log::expressions::attr< unsigned int >("LineID")
                << ": <" << boost::log::expressions::attr<SeverityLevel,severity_tag >("Severity")
                << "> " << boost::log::expressions::smessage)
    ); */

    std::stringstream s;
    s << "[Sinks.MySink]" << std::endl;
    s << "Destination=Console" << std::endl;
    s << "Format="%LineID%: <%Severity%> - %Message%"" << std::endl;
    boost::log::init_from_stream(s);

    boost::log::sources::severity_logger<SeverityLevel> lg;
    BOOST_LOG_SEV(lg,trace) << "This is a trace message";
    BOOST_LOG_SEV(lg,fatal) << "This is a fatal message";
    return 0;
}