qml程序退出时如何通知C++后台线程关闭

qml程序如果存在c++后台线程，那么在关闭qml主窗口时，必须先清理后台线程资源，并退出后台线程之后，才能正常退出程序。否则会报错：QThread: Destroyed while thread is still running

以下是代码：

int main(int argc, char *argv[])
{
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif
    //QGuiApplication app(argc, argv);
    QApplication app(argc, argv);
    app.setWindowIcon(QIcon(":/app.png"));

    //MainBackgroundProcess
    QThread threadProcess;
    MainBackgroundProcess::instance()->moveToThread(&threadProcess);
    QObject::connect(&threadProcess, &QThread::started, [=](){
        MainBackgroundProcess::instance()->init();
    });
    threadProcess.start();