Hi

I've some troubles with threading. In my application I've separated the GUI and a streaming/processing part into 2 threads. The streaming thread is created like the example in the QThread Class documentation. For a "single shot" that works great (starting and stopping the streaming thread). But if I re-click the streaming button the application crashes. There is no difference if I call the destructor for my background-worker class and recreate a complete new instance, or if I only re-call the thread start function.

Where is my problem?

Here are the specific parts:
Qt Code: 
  1. MainWindow::MainWindow(QWidget *parent) :
  2.     QMainWindow(parent),
  3.     ui(new Ui::MainWindow)
  4. {
  5.     backgroundWorker = new workerThread;
  6.     //Setup callback for cleanup when it finishes
  7.     connect(backgroundWorker, SIGNAL(finished()), backgroundWorker, SLOT(deleteLater()));
  8.     connect(backgroundWorker, SIGNAL(FrameReady()), this, SLOT(update_detection_lb()));
  9.  
  10.     connect(ui->StartStopStreaming_pb, SIGNAL(clicked()), this, SLOT(Streaming()));
  11.  
  12.     // Set gui labels
  13.     ui->Gain_lb->setText(QString("%1 dB").arg(backgroundWorker->gain));
  14.     ui->fc_lb->setText(QString("%1 MHz").arg(backgroundWorker->freq / 1e6));
  15.     ui->adr_lb->setText(QString::fromStdString(backgroundWorker->addr));
  16. }
  17.  
  18. // Streaming button
  19. void MainWindow::Streaming()
  20. {
  21.     if(ui->StartStopStreaming_pb->text() == "Start streaming")
  22.     {
  23.         ui->StartStopStreaming_pb->setText("Stop streaming");
  24.  
  25.         std::cout << "Start streaming in background thread" << std::endl;
  26.  
  27.         if(backgroundWorker)
  28.         {
  29.             backgroundWorker->m_abort = false;
  30.             backgroundWorker->start(QThread::HighestPriority);
  31.         }
  32.     }
  33.     else{
  34.         ui->StartStopStreaming_pb->setText("Start streaming");
  35.  
  36.         std::cout << "Stop streaming and terminate background thread" << std::endl;
  37.  
  38.         backgroundWorker->m_abort = true;
  39.         if(!backgroundWorker->wait(5000))
  40.         {
  41.             std::cout << "Thread deadlock detected, bad things may happen!" << std::endl;
  42.  
  43.             backgroundWorker->terminate();
  44.             backgroundWorker->wait();
  45.         }
  46.     }
  47. }
  48.  
  49. void workerThread::run()
  50. {
  51.     std::cout << "Thread running" << std::endl;
  52.  
  53.     while(m_abort == false)
  54.     {
  55. 	// Do some streaming stuff
  56.     }
  57.  
  58.     std::cout << "Thread terminated" << std::endl;
  59.     emit finished();
  60. }
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Best regards,
P51D