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I have a class that I want to appear in log in a certain way, so I've overloaded its << operator:

class CWindowClassId
{
public:
    // ...
    friend std::wostream& operator<< (std::wostream& os, CWindowClassId const& classId);
}

Inserting the class above in log stream:

// ...
CWindowClassId classId(hWindow);
BOOST_LOG_TRIVIAL(debug) << "Window created, class = " << classId;

causes compilation error:

Error   1   error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const Sandbox::CWindowClassId' (or there is no acceptable conversion)    C:\local\boost_1_55_0\boost\log\utility\formatting_ostream.hpp  710

I know the error lies in the fact, that I've overloaded << for wide strings. All is fine when I use ostream instead of wostream, but I really want to use wide string version.

I've tried to set locale for a sink:

shared_ptr<log::sinks::synchronous_sink<log::sinks::text_file_backend> > sink = log::add_file_log("log.txt");
sink->imbue(boost::locale::generator()("en_US.UTF-8"));

And have BOOST_LOG_USE_WCHAR_T defined before any log-related includes.

Is there anything I can do to make logging work with wide string << operator?

I'm using Boost 1.55.0.

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1 回答 1

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我不认为你可以用BOOST_LOG_TRIVIAL. trivial logger 使用底层boost::sources::logger而不是boost::sources::wlogger，您可以从 boost 源文件中的 trivial.hpp 和 trivial.cpp 中看到，除非我们修改源代码，否则我无法看到如何更改它。如果你使用 a wlogger，它会工作。这是一个例子：

#include <iostream>
#include <string>
#include <boost/log/sources/logger.hpp>
#include <boost/log/common.hpp>

namespace src = boost::log::sources;

class CWindowClassId
{
public:
    // ...
    friend std::wostream& operator<< (std::wostream& os, CWindowClassId const& classId)
    {
        os << classId.ws;
        return os;
    }
public:
    std::wstring ws;
};

int main(int argc, char* argv[])
{
    src::wlogger lg;
    CWindowClassId id;
    id.ws = L"wide char";
    BOOST_LOG(lg) << "Hello, World! This is a wide character message."<<id;
    return 0;
}
于 2014-04-11T03:21:54.690 回答