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Undefined reference to resizeEvent(QResizeEvent*)



  • My application includes a class “Parabola” which is a subclass of QOpenGLWindow, which is a subclass of QObject. The Parabola class includes the Q_OBJECT macro:

    #ifndef PARABOLAWINDOW_H
    #define PARABOLAWINDOW_H
    
    #include <QOpenGLWindow>
    #include <QOpenGLFunctions>
    #include <QOpenGLBuffer>
    #include <QOpenGLVertexArrayObject>
    #include <QMatrix4x4>
    
    class QOpenGLShaderProgram;
    
    class ParabolaWindow : public QOpenGLWindow,
                   protected QOpenGLFunctions
    {
      Q_OBJECT
    

    The project compiles, but the linker gives this result:

    g++ -Wl,-O1 -Wl,-rpath,/home/oreilly/Qt/5.14.2/gcc_64/lib -o parabola main.o ParabolaWindow.o qrc_qml.o moc_ParabolaWindow.o   /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5Quick.so /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5Gui.so /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5QmlModels.so /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5Qml.so /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5Network.so /home/oreilly/Qt/5.14.2/gcc_64/lib/libQt5Core.so -lGL -lpthread   
    
    moc_ParabolaWindow.o:(.data.rel.ro._ZTV14ParabolaWindow[_ZTV14ParabolaWindow]+0xa0): undefined reference to `ParabolaWindow::resizeEvent(QResizeEvent*)'
    collect2: error: ld returned 1 exit status
    Makefile:282: recipe for target 'parabola' failed
    make: *** [parabola] Error 1
    

    Parent class QOpenGLWindow defines method resizeEvent(QResizeEvent*), which is defined in libQt5Gui.so, and I am linking with that library. I have other projects that subclass QOpenGLWindow, yet they do not have this error when I link. What is causing this error?

    Thanks!


  • Lifetime Qt Champion

    @Tom-asso said in Undefined reference to resizeEvent(QResizeEvent*):

    resizeEvent

    You defined resizeEvent() in your class but did not implement it.


  • Lifetime Qt Champion

    Hi,

    Beside @Christian-Ehrlicher good point, you seem to have made it a slot which is wrong. This method will automatically be called but it is not a slot.



  • @Christian-Ehrlicher and @SGaist - thanks very much for help, and you are both right of course. Super-useful to have your additional eyes on my code!


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