converting from QString to wstring adding extra escape sequence

Question

I have a QString like

QString qReplaceByText("**\\g<char>**");

If I try to convert it to a wstring its replacing \ with \\

std::wstring wReplaceByText = qReplaceByText.toStdWString();

qReplaceByText becomes

**\\\\g<char>**

How can I avoid this ?

This is my code snippet

           std::wstring searchText(L"(?P<char>.)(?P=char)");;
            wsregex regExp;
            std::wstring strOut;
            try
            {
                regExp = wsregex::compile( searchText, boost::xpressive::icase );

                std::wstring wsObjectName =  L"tweet" ;

                std::wstring wReplaceByText = qReplaceByText.toStdWString();

                strOut.resize( wsObjectName.length() + wReplaceByText.length() );
                std::wstring::iterator itOut = strOut.begin();
                boost::xpressive::regex_replace(itOut, wsObjectName.begin() , wsObjectName.end(), regExp, wReplaceByText,  regex_constants::format_perl );
            }