Problems with setCentralWidget

[Rockem]

If you include QT in the Factory you loose the whole point
the point is to separate QT GUI from the program's logic
WidgetView is not a QWidget, but QTTextEdit which inherited from it IS
so I can.
this is strange, as the same code is working perfectly under Windows

I wrote a simplified program that show the problem:

#include <QtGui>
 
class CompView {
public:
	virtual ~CompView() {}
	virtual void eli() = 0;
};
 
class Comp : public QTextEdit, public CompView {
public:
	void eli() {}
};
 
int main(int argc, char *argv[]) {
	QApplication app(argc, argv);
	QMainWindow mw;
	CompView* c = new Comp;
	mw.setCentralWidget((QWidget*)c);
	mw.show();
	return app.exec();
}

#include <QtGui>

class CompView {
public:
	virtual ~CompView() {}
	virtual void eli() = 0;
};

class Comp : public QTextEdit, public CompView {
public:
	void eli() {}
};

int main(int argc, char *argv[]) {
	QApplication app(argc, argv);
	QMainWindow mw;
	CompView* c = new Comp;
	mw.setCentralWidget((QWidget*)c);
	mw.show();
	return app.exec();
}

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when I run this I also get segmentation fault