efficiently compare QString and std::string for equality

c++, qstring, qt, std, stdstring

Solution

`QString::fromStdString()` and `QString::toStdString()` comes to mind, but they create temporary copy of the string, so afaik, if you don't want to have temporary objects, you will have to write this function yourself (though what is more efficient is a question).

Example:

    QString string="string";
    std::string stdstring="string";
    qDebug()<< (string.toStdString()==stdstring); // true


    QString string="string";
    std::string stdstring="std string";
    qDebug()<< (str==QString::fromStdString(stdstring)); // false

By the way in qt5, `QString::toStdString()` now uses `QString::toUtf8()` to perform the conversion, so the Unicode properties of the string will not be lost (qt-project.org/doc/qt-5.0/qtcore/qstring.html#toStdString

Problem

I want to efficiently compare a QString and a std::string for (in)equality. Which is the best way to do it, possibly without creating intermediate objects?

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