Cann't write connect in main.cpp

L.Gogs

#include <QCoreApplication>
#include <QTimer>
#include <QObject>
#include <QDebug>

class Taz742 : public QObject
{
public:
    Taz742()
    {
        tm = new QTimer();
    }

    QTimer *tm;
    ~Taz742()
    {
        delete tm;
    }

public slots:
    void Print()
    {
        qDebug() << "Taz742";
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    Taz742 *L = new Taz742();
    L->tm->start(1000);
    L->connect(L->tm, SIGNAL(timeout()), L, SLOT(Print()));

    return a.exec();
}

on the black screen appears --> QObject::connect No such slot QObject::Print()
what is wrong in my code?

L.Gogs

This post is deleted!

m.sue

Hi @L.Gogs

Your class does not have a Q_OBJECT macro.

-Michael.

L.Gogs

@m.sue
yes I know but when I wrote it, I had errors

Pradeep Kumar

class Taz742 : public QObject
{
Q_OBJECT 
public:
    Taz742()
    {
        tm = new QTimer();
    }

    QTimer *tm;
    ~Taz742()
    {
        delete tm;
    }

public slots:
    void Print()
    {
        qDebug() << "Taz742";
    }
};

Thanks,

Pradeep Kumar

@L.Gogs

can u post what errors occurred.

Thanks,

L.Gogs

@Pradeep-Kumar
of course :))

undefined reference to 'vtable for Taz742'

L.Gogs

This post is deleted!

m.sue

Hi @L.Gogs

Your Taz742 destructor is virtual, by inheritance from QObject. A class with virtual functions should be defined in its own file: Taz742.cpp and Taz742.h

-Michael.

L.Gogs

@m.sue
Thanks...
but how can I write connect in main.cpp

m.sue

Hi @L.Gogs

Just #include the header file. Then you can use your class there

-Michael.

L.Gogs

@m.sue
no no, I want to write connect into main.cpp without any other header or cpp file.

m.sue

Hi @L.Gogs

To be blunt: You have to comply with the rules of the computer language (C++ in this case) or not use it. You cannot discuss such issues with the compiler/linker.

-Michael.

mrjj

@L.Gogs said in Cann't write connect in main.cpp:

no no, I want to write connect into main.cpp without any other header or cpp file.

https://stackoverflow.com/questions/34928933/why-is-important-to-include-moc-file-at-end-of-a-qt-source-code-file

You can hack it but using a .h file is the right way and besides this approach might have issues.
I never used it as its non common to only have .cpp file outside school projects.