title: Serialize / Deserialize QVariantMap with QDataStream between PyQt >> Qt-C++
body: <p>I can Successfully Serialize / Deserialize QVariantMap through  QDataStream in the PyQt5</p>
  <p>Python :</p>
  <pre><code>    data = {'mq_username': ('123'),  'np_database': ('png') ,  'category': ('png') ,  'enroll_name': ('png') ,  'notes': ('png') ,   'file': ('png') ,
              'np_database': ('png') , 'PNG-image': (png) }
      v = QVariant(data)
  block = QByteArray()
      xout = QDataStream(block, QIODevice.WriteOnly)
      xout.setVersion(qt.QDataStream.Qt_5_10)
      xout &lt;&lt; v
      xox = (b'')
      xox = block.data()
  </code></pre>
  <p>This is perfectly fine to deserialize:</p>
  <pre><code>out = qt.QDataStream(block, qt.QIODevice.ReadOnly)
          out.setVersion(qt.QDataStream.Qt_5_10)
  
          keys = out.readQVariant()
  </code></pre>
  <p>I can get all item at keys.</p>
  <p>But I can not get it from the C++.</p>
  <p>How can I get this QDataStream (QVariantMap)  from c++ ?</p>
  <pre><code>    QVariantMap *vmat_x;
  
      QDataStream stream(message);
      stream.setVersion(QDataStream::Qt_5_10);
      stream &gt;&gt; vmat_x ;
  </code></pre>
  <p>vmat_x is always empty</p>
  <p>any idea ?</p>
  <p>EDIT:</p>
  <p>message is QBytearray coming from Python xox</p>