QThread - Using a slot to exit the thread

[johnnyturbo3]

Hi,

I want to inform an object when a thread has finished running. However, I cannot get the thread to exit properly. I have the following code:

Processor.cpp

thread = new QThread;
tw = new ThreadWorker;
connect(tw, SIGNAL(updateStatus(QString)), this, SLOT(statusUpdate(QString)));
tw->doSetup(thread, strDic);
tw->moveToThread(thread);
thread->start();
 
while(thread->isRunning())
{
}
 
qDebug() << "Thread Finished";

thread = new QThread;
tw = new ThreadWorker;
connect(tw, SIGNAL(updateStatus(QString)), this, SLOT(statusUpdate(QString)));
tw->doSetup(thread, strDic);
tw->moveToThread(thread);
thread->start();
	
while(thread->isRunning())
{
}
	
qDebug() << "Thread Finished";

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ThreadWorker.cpp

void ThreadWorker::doSetup(QThread *thread, const string &path)
{
  _strPath = path;
  connect(thread, SIGNAL(started()), this, SLOT(run()));
  connect(this, SIGNAL(finished()), thread, SLOT(quit())); //tried terminate() also
}
 
 
void ThreadWorker::run()
{
  DirectorySearch dicSearch;
  vector<string> vecFileList = dicSearch.getFileList(_strPath);
  emit updateStatus("Directory Fetched");
  emit finished();
}

void ThreadWorker::doSetup(QThread *thread, const string &path)
{
  _strPath = path;
  connect(thread, SIGNAL(started()), this, SLOT(run()));
  connect(this, SIGNAL(finished()), thread, SLOT(quit())); //tried terminate() also
}


void ThreadWorker::run()
{
  DirectorySearch dicSearch;
  vector<string> vecFileList = dicSearch.getFileList(_strPath);
  emit updateStatus("Directory Fetched");
  emit finished();
}

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The quit() slot does not seem to stop the thread (QThread::isFinished never returns true). Can someone guide me in the right direction?

Thanks in advance

[mcosta]

Have you called ThreadWorker::exec() ??

If you don't ThreadWorker doesn't launch eventLoop and so doesn't receive signals

[johnnyturbo3]

The ThreadWorker class doesn't inherit from QThread. So it has no exec() method.

[mcosta]

Is ThreadWorker derived from QObject?

can you post ThreadWorker definition (header file)?

[johnnyturbo3]

class ThreadWorker : public QObject
{
  Q_OBJECT
 
public:
  ThreadWorker(void);
  ~ThreadWorker(void);
 
 
  void doSetup(QThread *, const string &);
 
public slots:
  void run();
 
signals:
  void updateStatus(QString);
  void finished();
 
private:
  DirectorySearch dicSearch;
  string _strPath;
};

class ThreadWorker : public QObject
{
  Q_OBJECT

public:
  ThreadWorker(void);
  ~ThreadWorker(void);


  void doSetup(QThread *, const string &);

public slots:
  void run();

signals:
  void updateStatus(QString);
  void finished();

private:
  DirectorySearch dicSearch;
  string _strPath;
};

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[mcosta]

When you call QObject::moveToThread, you obtain some warning messages in console?

Do you tried to start the thread before to move ThreadWorker?

[johnnyturbo3]

I think I understand what's happening now.

The main thread is being kept busy by the
while(thread->isRunning())
{
}

Therefore, it cannot process any signals being sent by the ThreadWorker.cpp

[mcosta]

I thought that you omitted some line of code

while(thread->isRunning())
{
...
}

while(thread->isRunning())
{
...
}

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PS. As general rule isn't correct to wait thread termination in this way.