Problem with declaring Metatype in Qt

Question

Hello folks,
I am trying to declare my Class as Metatype for Qt but figuring out some problems. It seems that after the MetaType declaration he wants to get access to a copy constructor or something like this which is explicitly not allowed for QObjects as I thought.
This is my header:

#include <QtCore/QObject>
#include <QtCore/QMetaType>

class Message : private QObject
{
  Q_OBJECT

public:
  Message();

  int sourceId;
  int targetId;

private:
  Q_DISABLE_COPY(Message)
};

Q_DECLARE_METATYPE(Message)
Q_DECLARE_METATYPE(Message*)

Message::Message() :
  QObject()
{
}  

So, I get the following errors:

Message::Message : cannot access private member declared in class Message see reference to function template instantiation 'void *qMetaTypeConstructHelper(const T *)' being compiled

and some more, but I think they are nearly the same and because of the same problem.
Someone knows what I am doing wrong?

Answer 1

You have to publicly inherit from QObject:

class Message : public QObject

By doing that, you don't need to declare metatype for class Message. Only for the pointer.