Undefined reference to signal



  • Hello everyone:

    Thanks for reading this post and being able to help.

    I would like to create a signal to call a slot in another class.

    My code looks like:

    header:

    class scene_mouse_event : public QGraphicsScene
    {
    
        Q_OBJECT
    
    public:
            scene_mouse_event(QObject* parent = 0);
    
            void mousePressEvent(QGraphicsSceneMouseEvent *event);
            QPointF pt;
    
    
    signals:
            void emit_mouse_pressed();
    
    
    };
    
    #endif // SCENE_MOUSE_EVENT_H
    

    .cpp

    #include "mainwindow.h"
    #include "ui_mainwindow.h"
    #include <QtGui>
    #include <QApplication>
    #include "scene_mouse_event.h"
    
    
    scene_mouse_event::scene_mouse_event(QObject* parent): QGraphicsScene(parent){
    
    }
    
    void scene_mouse_event::mousePressEvent(QGraphicsSceneMouseEvent *event)
    {
        this->pt = event->scenePos();
        emit emit_mouse_pressed();
        QGraphicsScene::mousePressEvent(event);
    }
    
    

    but it gives me an error in "emit emit_mouse_pressed();":
    scene_mouse_event.cpp:15: error: undefined reference to `scene_mouse_event::emit_mouse_pressed()'

    and this in the constructor:
    scene_mouse_event.cpp:8: error: undefined reference to `vtable for scene_mouse_event'

    What's happening?
    Thanks!


  • Qt Champions 2016

    hi, you need to run qmake from the build menu.
    if it still stupid, then clean the build folder and rebuild all :)


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