undefined reference to `vtable for ... ', specific for QT projects...

[jiapei100]

Seriously have no idea why this happens, particularly, always happening in QT projects.

../utils/bin/Debug/libutils.a(ImageView.o): In function `CImageView':
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
../utils/bin/Debug/libutils.a(ImageView.o): In function `~CImageView':
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:23: undefined reference to `vtable for CImageView'
../utils/bin/Debug/libutils.a(ImageView.o):/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:23: more undefined references to `vtable for CImageView' follow
collect2: ld returned 1 exit status
make: *** [objdetection] Error 1

../utils/bin/Debug/libutils.a(ImageView.o): In function `CImageView':
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:13: undefined reference to `vtable for CImageView'
../utils/bin/Debug/libutils.a(ImageView.o): In function `~CImageView':
/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:23: undefined reference to `vtable for CImageView'
../utils/bin/Debug/libutils.a(ImageView.o):/home/jiapei/MyPrograms/codeblocks/aam/utils/src/ImageView.cpp:23: more undefined references to `vtable for CImageView' follow
collect2: ld returned 1 exit status
make: *** [objdetection] Error 1

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It seems to tell than CImageView is missing something .

My CImageView is defined as:

#ifndef __IMAGEVIEW_QT__
#define __IMAGEVIEW_QT__
 
#include <QGraphicsView>
#include <QLabel>
#include <QBoxLayout>
 
 
#include "cv.h"
#include "highgui.h"
 
using namespace std;
using namespace cv;
 
/**
show an image in the corresponding wxWindow
*/
class CImageView : public QGraphicsView
{
	Q_OBJECT
 
private:
	bool					m_isDrawing;
	QGraphicsScene*			m_QTScene;
	QImage*					m_QTImage;
protected:
	void					paintEvent(QPaintEvent *event);
 
public:
    CImageView( QWidget *parent = 0 );
    virtual                 ~CImageView( );
 
    //CImageView&             operator=(const CImageView& iImgView);
 
	void					putImage(const Mat& image);
};
 
#endif  // __IMAGEVIEW_QT__

#ifndef __IMAGEVIEW_QT__
#define __IMAGEVIEW_QT__

#include <QGraphicsView>
#include <QLabel>
#include <QBoxLayout>


#include "cv.h"
#include "highgui.h"

using namespace std;
using namespace cv;

/**
show an image in the corresponding wxWindow
*/
class CImageView : public QGraphicsView
{
	Q_OBJECT

private:
	bool					m_isDrawing;
	QGraphicsScene*			m_QTScene;
	QImage*					m_QTImage;
protected:
	void					paintEvent(QPaintEvent *event);

public:
    CImageView( QWidget *parent = 0 );
    virtual                 ~CImageView( );

    //CImageView&             operator=(const CImageView& iImgView);

	void					putImage(const Mat& image);
};

#endif  // __IMAGEVIEW_QT__

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And, I'm pretty sure that none of the functions is not defines.
Namely, all declared functions have been defined in .cpp files !!!!

So, the only possibility is " QGraphicsView " is not defined.


Am I correct? How to avoid such error messages ?

Please do help !!!

Best Regards
JIA

[wysota]

Rerun qmake after adding the Q_OBJECT macro to an existing file and make sure all virtual methods that are declared, are also implemeneted.

[jiapei100]

Yes, as you might have seen in my header file

#ifndef __IMAGEVIEW_QT__
#define __IMAGEVIEW_QT__
 
#include <QGraphicsView>
#include <QLabel>
#include <QBoxLayout>
 
 
#include "cv.h"
#include "highgui.h"
 
using namespace std;
using namespace cv;
 
/**
show an image in the corresponding wxWindow
*/
class CImageView : public QGraphicsView
{
	[SIZE="6"][B]Q_OBJECT   // declared !!!!!!!!![/B][/SIZE]
 
private:
	bool					m_isDrawing;
	QGraphicsScene*			m_QTScene;
	QImage*					m_QTImage;
protected:
	void					paintEvent(QPaintEvent *event);
 
public:
    CImageView( QWidget *parent = 0 );
    virtual                 ~CImageView( );
 
    //CImageView&             operator=(const CImageView& iImgView);
 
	void					putImage(const Mat& image);
};
 
#endif  // __IMAGEVIEW_QT__

#ifndef __IMAGEVIEW_QT__
#define __IMAGEVIEW_QT__

#include <QGraphicsView>
#include <QLabel>
#include <QBoxLayout>


#include "cv.h"
#include "highgui.h"

using namespace std;
using namespace cv;

/**
show an image in the corresponding wxWindow
*/
class CImageView : public QGraphicsView
{
	[SIZE="6"][B]Q_OBJECT   // declared !!!!!!!!![/B][/SIZE]

private:
	bool					m_isDrawing;
	QGraphicsScene*			m_QTScene;
	QImage*					m_QTImage;
protected:
	void					paintEvent(QPaintEvent *event);

public:
    CImageView( QWidget *parent = 0 );
    virtual                 ~CImageView( );

    //CImageView&             operator=(const CImageView& iImgView);

	void					putImage(const Mat& image);
};

#endif  // __IMAGEVIEW_QT__

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What's more, the only virtual function (destructor) has been absolutely defined in the .cpp file as:

CImageView::~CImageView( )
{
	if(this->m_QTImage)			delete (this->m_QTImage);
	if(this->m_QTScene)			delete (this->m_QTScene);
}

CImageView::~CImageView( )
{
	if(this->m_QTImage)			delete (this->m_QTImage);
	if(this->m_QTScene)			delete (this->m_QTScene);
}

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Why QT always brings such kind of weird error messages, while other projects don't ?
Any more detailed explanation what's actually happening inside QT project that might have caused this?


Cheers
JIA

Rerun qmake after adding the Q_OBJECT macro to an existing file and make sure all virtual methods that are declared, are also implemeneted.

[wysota]

Yes, as you might have seen in my header file

I asked you if you ran qmake after setting the macro and not if you declared it.

Why QT always brings such kind of weird error messages, while other projects don't ?

Ask Apple, QuickTime is their product.