[Qt-interest] qobject_cast<>() and objects from dynamically loaded libraries

[Dmitry Nezhevenko]

Hi guys.

I'm experiencing strange behaviour of QObject cast. Basically I've code
like:

class Base: public QWidget
{
	Q_OBJECT
};

class SomeImpl: public Base
{
	Q_OBJECT
};

On Win32 I have some function DLL-exported that returns pointer to QWidget:

QWidget *getWidget();

After loading library (LoadLibrary && GetProcAddress) and calling to 
getWidget() I'm trying to cast returned pointer to Base:

	Base *b = qobject_cast<Base *>(w);

And b = 0 here. I'm sure that w is correct pointer. For example I can do:

	QString className = w->metaObject()->className();

And className became "SomeImpl". Also debugger shows that w is instance of SomeImpl 
and contains Base.

Also dynamic_cast works as expected. Any ideas why qobject_cast returns
zero?

PS. Qt 4.4.3, MSVC2005

-- 
WBR, Dmitry
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