Hello everyone,
I am trying to make some parts of my app run in a different thread than th UI thread, meanwhile I am trying to use a timer to show the elapsed time on the form.
For this I used the QConcurrent::run method like this :
Qt Code: 
  1. void frmCustomNetwork::on_btnTrain_clicked()
  2. {
  3.   try
  4.   {
  5.       if( P.size() == 0 || T.size() == 0)
  6.       {
  7. 	QMessageBox::warning(this,"No Sample for training is set","You need to specify some samples with their respective desired outputs first");
  8. 	return;
  9.       }
  10.  
  11.  
  12.       elapsedSeconds=0;
  13.       timer->start();
  14.       connect(&watcher,SIGNAL(finished()),this,SLOT(on_TimerTick()));
  15.       future = QtConcurrent::run(this,&frmCustomNetwork::Rec,ui->chkPlot->isChecked());
  16.       watcher.setFuture(future);
  17.  
  18.   }
  19.   catch(std::exception ex)
  20.   {
  21.     QMessageBox::critical(this,"Exception occured in on_btnTrain_clicked()",ex.what());
  22.   }
  23.   catch(...)
  24.   {
  25.     QMessageBox::critical(this,"Exception occured on_btnTrain_clicked()","Uknown Exception occured");
  26.   }
  27. }
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and this is the timerTick slot:
Qt Code: 
  1. void frmCustomNetwork::on_TimerTick()
  2. {
  3.   elapsedSeconds++;
  4.   if(watcher.isFinished())
  5.   {
  6.     timer->stop();
  7.     elapsedSeconds = 0;
  8.     return;
  9.   }
  10.  
  11.   day = elapsedSeconds / (24*3600);
  12.   hour = (elapsedSeconds % (24*3600)) / 3600 ;
  13.   min = ((elapsedSeconds % (24*3600)) % 3600) / 60;
  14.   second = ((elapsedSeconds % (24*3600)) % 3600) % 60;
  15.  
  16.   ui->lblElapsedTime->setText(QString::number(day)+" : "+QString::number(hour)+" : "+QString::number(min)+" : "+QString::number(second));
  17. }
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the problem that I am facing now is :
1.Is it the correct way of using QConcurent in first place?
2.How can I destroy the running thread ( the one spawned by QConcurrect::run()) when the window closes ( that is when the Rec() is not finished yet and is being executed in a separate thread, I suddently decide to close the app)

at the moment I am facing random crashes which I guess pretty much is because of the way I am creating and dealing with the new thread + timer.
I would be grateful If anyone could give me a hand in this
Thanks in advance