How to end a QThread correct in main.cpp?

[robro]

Hello,
I have a problem with ending a QThread.

In my main.cpp I connect the "aboutToQuit" signal to call the destructor of the used class. Its destructor emits a "finished" signal which then tells the corresponding thread to quit.
Now I need to wait until the thread quits before the application quits.
Here is my problem. I have no clue how to do that.

How can I properly end my thread and my application?

Thanks

Used MyClass slot:

public slots:
    void quit(){delete this;} //Calls destructor which emits “finished” signal

Main.cpp:

#include <QApplication>
#include <QQmlApplicationEngine>
#include <QThread>
#include "myclass.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MyClass* myClass = new MyClass();

    QThread myClassThread;
    QObject::connect(&app, &QApplication::aboutToQuit, myClass, &MyClass::quit);
    QObject::connect(myClass, &MyClass::finished,  &myClassThread, &QThread::quit);
    myClass->moveToThread(&myClassThread);
    myClassThread.start();

    QQmlApplicationEngine engine;
    const QUrl url(QStringLiteral("qrc:/main.qml"));
    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
    engine.load(url);

    return app.exec();
}

[jsulm]

@robro Call https://doc.qt.io/qt-5/qthread.html#quit and then https://doc.qt.io/qt-5/qthread.html#wait

[robro]

@jsulm said in How to end a QThread correct in main.cpp?:

@robro Call https://doc.qt.io/qt-5/qthread.html#quit and then https://doc.qt.io/qt-5/qthread.html#wait

Thanks, but how?
Calling wait after "return app.exec();" would not work and I have no clue to call wait using the signal slot mechanism.

[JKSH]

@robro said in How to end a QThread correct in main.cpp?:

Calling wait after "return app.exec();" would not work

Return after waiting:

int exitCode = app.exec();
myClassThread.wait();
return exitCode;

void quit(){delete this;} //Calls destructor which emits “finished” signal

Beware: In general, deleting a QObject in a slot is dangerous. It could cause your program to crash if other signals arrive.

You don't need MyClass::quit() -- just connect QApplication::aboutToQuit() to MyClass::deleteLater().