[Interest] QDataStream not increasing position of QByteArray

[Stephan.Ebeling at hs-anhalt.de]

Dear Qt-list-members,



i got the following problem with Qt and i hope that you can help me:


When I write raw network bytes to a QDataStream object repeatedly, the QDataStream never increases the write position of the underlying QByteArray.

Here's the code:

QByteArray recvBuf;
int bytePosition = 0;

void init( ){
    recvBuf = QByteArray( 240 * 10, Qt::Uninitiliazed );
}

void receiveAppend( ){
    QByteArray buffer( 240, Qt::Uninitialized );
    QDataStream datastream( recvBuf, QIODevice::WriteOnly );
    datastream.setByteOrder( QDataStream::LittleEndian );

    if( udpSocket->readDataGram( buffer.data(), buffer.size(), &ip, &port ){
        datastream.device().seek( bytePosition );
        datastream.writeRawData( buffer.data(), buffer.size() );
        bytePosition += 240;
    }
}


Why is this happening?

The code works fine on Linux Mint 18 64Bit. But it's not working on Windows 10 64Bit. I'm using Qt Creator 4.3.1 with Qt 5.9.1.


I appreciate your help.


Best regards

Stephan Ebeling
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