undefined reference to `vtable for MyWidget'

[onder]

hi i wrote small hello world program but i am taking error like this :

g++ -Wl,-rpath,/usr/qt/4/lib -o sllot mayn.o -L/usr/qt/4/lib -lQtGui -L/var/tmp/pisi/qt4-4.1.4-5/work/qt-x11-opensource-src-4.1.4/lib -L/usr/X11R6/lib -lpng -lSM -lICE -lXi -lXrender -lXrandr -lXcursor -lXinerama -lfreetype -lfontconfig -lXext -lX11 -lQtCore -lz -lm -ldl -lpthread
mayn.o: In function `MyWidget::MyWidget(QWidget*)':
mayn.cpp:(.text+0x31): undefined reference to `vtable for MyWidget'
mayn.cpp:(.text+0x3d): undefined reference to `vtable for MyWidget'
mayn.o: In function `MyWidget::MyWidget(QWidget*)':
mayn.cpp:(.text+0x1db): undefined reference to `vtable for MyWidget'
mayn.cpp:(.text+0x1e2): undefined reference to `vtable for MyWidget'
mayn.o: In function `MyWidget::~MyWidget()':
mayn.cpp:(.text+0x354): undefined reference to `vtable for MyWidget'
mayn.o:mayn.cpp:(.text+0x35b): more undefined references to `vtable for MyWidget' follow
collect2: ld returned 1 exit status
make: *** [sllot] Hata 1

my code is :

#include <QApplication>
#include <QFont>
#include <QPushButton>
#include <QWidget>
#include <QMessageBox>
 
class MyWidget : public QWidget
{
      Q_OBJECT
public:
	QPushButton *btn;
       MyWidget(QWidget *parent = 0);
 
	~MyWidget();
	{
	delete btn;
	}
 
public slots:
       void test()      
       {
           QMessageBox::information(this, "mesaj", "merhaba dunya");         
       }
};
 
       MyWidget::MyWidget(QWidget *parent ): QWidget(parent)
       {
           setFixedSize(150,100);
           btn = new QPushButton("tikla", this);
           btn->setGeometry(50,30,50,30);
 
           connect(btn,SIGNAL(clicked()),this,SIGNAL(test()));                 
 
       }
	MyWidget::~MyWidget()
	{
	delete btn;
	}
 
int main(int argc, char *argv[])
{
    QApplication app (argc,argv);
    MyWidget widget;
    widget.show();
    return app.exec();
}

#include <QApplication>
#include <QFont>
#include <QPushButton>
#include <QWidget>
#include <QMessageBox>

class MyWidget : public QWidget
{
      Q_OBJECT
public:
	QPushButton *btn;
       MyWidget(QWidget *parent = 0);

	~MyWidget();
	{
	delete btn;
	}

public slots:
       void test()      
       {
           QMessageBox::information(this, "mesaj", "merhaba dunya");         
       }
};

       MyWidget::MyWidget(QWidget *parent ): QWidget(parent)
       {
           setFixedSize(150,100);
           btn = new QPushButton("tikla", this);
           btn->setGeometry(50,30,50,30);
          
           connect(btn,SIGNAL(clicked()),this,SIGNAL(test()));                 
        
       }
	MyWidget::~MyWidget()
	{
	delete btn;
	}

int main(int argc, char *argv[])
{
    QApplication app (argc,argv);
    MyWidget widget;
    widget.show();
    return app.exec();
}

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i am using qt 4.1.4
whats wrong?
thanks a lot

Onder Arslan

[jpn]

The constructor does not have an implementation body?
If you decide not to separate your class declaration into a header file, you will have to include the appropriate moc file somewhere in your .cpp file.

#include <QApplication>
#include <QFont>
#include <QPushButton>
#include <QWidget>
#include <QMessageBox>
 
class MyWidget : public QWidget
{
      Q_OBJECT
public:
        QPushButton *btn;
       MyWidget(QWidget *parent = 0)
       {
              // supply at least an empty body
       }
 
        ~MyWidget();
        {
        delete btn;
        }
 
public slots:
       void test()      
       {
           QMessageBox::information(this, "mesaj", "merhaba dunya");         
       }
};
 
// you will have to include moc file in case you don't use a separate header which is recommended..
#include "mayn.moc"

#include <QApplication>
#include <QFont>
#include <QPushButton>
#include <QWidget>
#include <QMessageBox>

class MyWidget : public QWidget
{
      Q_OBJECT
public:
        QPushButton *btn;
       MyWidget(QWidget *parent = 0)
       {
              // supply at least an empty body
       }

        ~MyWidget();
        {
        delete btn;
        }

public slots:
       void test()      
       {
           QMessageBox::information(this, "mesaj", "merhaba dunya");         
       }
};

// you will have to include moc file in case you don't use a separate header which is recommended..
#include "mayn.moc"

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And re-run qmake so moc will be run on this file next time.

[onder]

thanks a lot.
it's working now

Onder