CODEWITHSUNDEEP
c++qtsignalsqthread
Wildhammer
Wildhammer

Reputation: 2175

how to emit signal inside run function of QThread?

I wrote a simple program which emits signal inside run function of a QThread inherited class and in another class which inherits QObject wrote a slot to catch the signal, but when I compile the code I get the following errors:

symbols(s) not found for architecture x86_64 collect2: ld returned 1 exit status

and here is my code :

class visionThread : public QThread
{
public:
    visionThread();
    void run();
signals:
    void newVisionPacket();
};

visionThread::visionThread():QThread(){
}

void visionThread::run()
{
    for(int i = 0 ; i<10 ; i++)
    {
        emit newVisionPacket();
        usleep(1000);
    }
}


class dummyClass: public QObject{
public:
    dummyClass(){
    }

    void doConnect(visionThread* v){
        connect(v , SIGNAL(newVisionPacket()) , this , SLOT(mySlot()));
    }
public slots:
    void mySlot(){
        usleep(2000);
        qDebug() << "HI" << endl;
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    visionThread *vision;

    vision = new visionThread();

    dummyClass *dummyObject = new dummyClass();

    dummyObject->doConnect(vision);

    vision->start(QThread::NormalPriority);

    return a.exec();
}

I'm so confused, and I would deeply appreciate any solutions.

Upvotes: 3

Views: 1347

Answers (1)

Nejat
Nejat

Reputation: 32635

You have not placed Q_OBJECT macro in your classes.They should be like:

class visionThread : public QThread
{
    Q_OBJECT
public:
    visionThread();
    void run();
signals:
    void newVisionPacket();
};

And

class dummyClass: public QObject{
    Q_OBJECT
public:
    dummyClass(){
    }

    void doConnect(visionThread* v){
        connect(v , SIGNAL(newVisionPacket()) , this , SLOT(mySlot()));
    }
public slots:
    void mySlot(){
        usleep(2000);
        qDebug() << "HI" << endl;
    }
};

After adding the Q_OBJECT macro Clean the project, run qmake and rebuild it.

Upvotes: 4

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