[Qt-interest] XmlPatterns fustration

[Jason H]

I have a simple document:
<a><div class="x"></div></a>

Want to find "x" so I use /a/div/@class/string()

But my query does not work:

QBuffer device; 
device.setData(sourceDoc.toUtf8());
device.open(QIODevice::ReadOnly);
QXmlQuery query;

query.setQuery("declare variable $inputDocument external;\r\n"
                "doc($inputDocument)"+ path);

query.bindVariable("inputDocument", &device);
QString result;
query.evaluateTo(&result);

The above setQuery line gives me the error:
"No value is available for the external variable with name inputDocument."

When I change it to:
query.setQuery("doc($inputDocument)"+ path);

I get:
No variable with name inputDocument exists

So what am I oing wrong?