QIODevice conversion to / from std::i(o)stream

[TorAn]

I have to use QIODevice in overloaded operators << and >> where std::i(o)streams are passed-in as arguments.

I'll appreciate the advice (or code ) for the wrapper that will allow me to initialize QIODevice instance with standard streams.
Example of what I am trying to accomplish:

std::ostream& operator << (std::ostream& s, const myClass& a)
{
    int i = 5;
    s << i;
    QIODevice device; // somehow wrap stream "s" to be QIODevice instance.
    QXmlStreamWriter writer(&device);
    writer.writeStartDocument("1.0");
..
    return s;
}

std::ostream& operator << (std::ostream& s, const myClass& a)
{
    int i = 5;
    s << i;
    QIODevice device; // somehow wrap stream "s" to be QIODevice instance.
    QXmlStreamWriter writer(&device);
    writer.writeStartDocument("1.0");
..
    return s;
}

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[ChrisW67]

Why not just stream your XML into a QBuffer and then access the raw character buffer of the internal QByteArray to send it to the std::ostream using write()?

[TorAn]

ChrisW67, thanks, that is similar to what I am doing now. But it would be nice to have smth like
QIODeviceWrapper dw (stdstream);
that would handle all internals .

[wysota]

You can make your wrapper do exactly what Chris suggests. Writing to an ostream is easy, reading from an istream is harder since the latter doesn't provide any notification upon receiving data.