#include <QCoreApplication>

class WorkerThread : public QThread
{
public:
    void run() {
        while(true)
        {
            /*
             * this thread won't work if you set the system time 
             * during the thread's running
             * example:
             *  first run this application
             *  if nowtime is 3:50pm you can set system time to 2:50pm
             *  look the console to determin if thread running
             */
            
            qDebug() << "HelloWorld";
            this->msleep(2000); 
            
        }
    }
};

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

    WorkerThread *workerThread = new WorkerThread();
    workerThread->start();

    QCoreApplication a(argc, argv);

    return a.exec();
}