[SOLVED] Qt: Signals and slots Error: undefined reference to `vtable for

[TheIndependentAquarius]

Following example from this link: http://developer.kde.org/documentati...3lev1sec3.html

#include <QObject>
    #include <QPushButton>
    #include <iostream>
    using namespace std;
 
    class MyWindow : public QWidget
    {
        Q_OBJECT  // Enable slots and signals
        public:
            MyWindow();
        private slots:
            void slotButton1();
            void slotButton2();
            void slotButtons();
        private:
            QPushButton *button1;
            QPushButton *button2;
    };
 
    MyWindow :: MyWindow() : QWidget()
    {
        // Create button1 and connect button1->clicked() to this->slotButton1()
        button1 = new QPushButton("Button1", this);
        button1->setGeometry(10,10,100,40);
        button1->show();
        connect(button1, SIGNAL(clicked()), this, SLOT(slotButton1()));
 
        // Create button2 and connect button2->clicked() to this->slotButton2()
        button2 = new QPushButton("Button2", this);
        button2->setGeometry(110,10,100,40);
        button2->show();
        connect(button2, SIGNAL(clicked()), this, SLOT(slotButton2()));
 
        // When any button is clicked, call this->slotButtons()
        connect(button1, SIGNAL(clicked()), this, SLOT(slotButtons()));
        connect(button2, SIGNAL(clicked()), this, SLOT(slotButtons()));
    }
 
    // This slot is called when button1 is clicked.
    void MyWindow::slotButton1()
    {
        cout << "Button1 was clicked" << endl;
    }
 
    // This slot is called when button2 is clicked
    void MyWindow::slotButton2()
    {
        cout << "Button2 was clicked" << endl;
    }
 
    // This slot is called when any of the buttons were clicked
    void MyWindow::slotButtons()
    {
        cout << "A button was clicked" << endl;
    }
 
    int main ()
    {
        MyWindow a;
    }

#include <QObject>
    #include <QPushButton>
    #include <iostream>
    using namespace std;
    
    class MyWindow : public QWidget
    {
        Q_OBJECT  // Enable slots and signals
        public:
            MyWindow();
        private slots:
            void slotButton1();
            void slotButton2();
            void slotButtons();
        private:
            QPushButton *button1;
            QPushButton *button2;
    };
      
    MyWindow :: MyWindow() : QWidget()
    {
        // Create button1 and connect button1->clicked() to this->slotButton1()
        button1 = new QPushButton("Button1", this);
        button1->setGeometry(10,10,100,40);
        button1->show();
        connect(button1, SIGNAL(clicked()), this, SLOT(slotButton1()));
        
        // Create button2 and connect button2->clicked() to this->slotButton2()
        button2 = new QPushButton("Button2", this);
        button2->setGeometry(110,10,100,40);
        button2->show();
        connect(button2, SIGNAL(clicked()), this, SLOT(slotButton2()));
        
        // When any button is clicked, call this->slotButtons()
        connect(button1, SIGNAL(clicked()), this, SLOT(slotButtons()));
        connect(button2, SIGNAL(clicked()), this, SLOT(slotButtons()));
    }
    
    // This slot is called when button1 is clicked.
    void MyWindow::slotButton1()
    {
        cout << "Button1 was clicked" << endl;
    }
      
    // This slot is called when button2 is clicked
    void MyWindow::slotButton2()
    {
        cout << "Button2 was clicked" << endl;
    }
      
    // This slot is called when any of the buttons were clicked
    void MyWindow::slotButtons()
    {
        cout << "A button was clicked" << endl;
    }
    
    int main ()
    {
        MyWindow a;
    }

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results in:

[13:33:45 Mon May 02] ~/junkPrograms/src/nonsense  $ls
nonsense.pro  signalsSlots.cpp
 
[13:33:46 Mon May 02] ~/junkPrograms/src/nonsense  $qmake
[13:33:50 Mon May 02] ~/junkPrograms/src/nonsense  $make
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/opt/qtsdk-2010.05/qt/mkspecs/linux-g++-64 -I. -I/opt/qtsdk-2010.05/qt/include/QtCore -I/opt/qtsdk-2010.05/qt/include/QtGui -I/opt/qtsdk-2010.05/qt/include -I. -I. -o signalsSlots.o signalsSlots.cpp
g++ -m64 -Wl,-O1 -Wl,-rpath,/opt/qtsdk-2010.05/qt/lib -o nonsense signalsSlots.o    -L/opt/qtsdk-2010.05/qt/lib -lQtGui -L/opt/qtsdk-2010.05/qt/lib -L/usr/X11R6/lib64 -lQtCore -lpthread
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x1a2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x1aa): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x3e2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x3ea): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `main':
signalsSlots.cpp:(.text+0x614): undefined reference to `vtable for MyWindow'
signalsSlots.o:signalsSlots.cpp:(.text+0x61d): more undefined references to `vtable for MyWindow' follow
collect2: ld returned 1 exit status
make: *** [nonsense] Error 1

[13:33:45 Mon May 02] ~/junkPrograms/src/nonsense  $ls
nonsense.pro  signalsSlots.cpp

[13:33:46 Mon May 02] ~/junkPrograms/src/nonsense  $qmake
[13:33:50 Mon May 02] ~/junkPrograms/src/nonsense  $make
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/opt/qtsdk-2010.05/qt/mkspecs/linux-g++-64 -I. -I/opt/qtsdk-2010.05/qt/include/QtCore -I/opt/qtsdk-2010.05/qt/include/QtGui -I/opt/qtsdk-2010.05/qt/include -I. -I. -o signalsSlots.o signalsSlots.cpp
g++ -m64 -Wl,-O1 -Wl,-rpath,/opt/qtsdk-2010.05/qt/lib -o nonsense signalsSlots.o    -L/opt/qtsdk-2010.05/qt/lib -lQtGui -L/opt/qtsdk-2010.05/qt/lib -L/usr/X11R6/lib64 -lQtCore -lpthread
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x1a2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x1aa): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `MyWindow::MyWindow()':
signalsSlots.cpp:(.text+0x3e2): undefined reference to `vtable for MyWindow'
signalsSlots.cpp:(.text+0x3ea): undefined reference to `vtable for MyWindow'
signalsSlots.o: In function `main':
signalsSlots.cpp:(.text+0x614): undefined reference to `vtable for MyWindow'
signalsSlots.o:signalsSlots.cpp:(.text+0x61d): more undefined references to `vtable for MyWindow' follow
collect2: ld returned 1 exit status
make: *** [nonsense] Error 1

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What's the reason of error here? I did a make clean and then make, it hasn't helped!