[Qt-interest] bloody ungraspable control of my pusbutton

[Roland Tollenaar]

connect to a function:
OnApplicationFinish(),

then in that something like:

cout<<"Waiting for threads to stop...."<<flush;
	while((EnquiryTWThreadRefresh->isRunning())||(ProductTWThreadRefresh->isRunning())){
	Sleep(10);
}
cout<<"done."<<endl;

is what I do.

HTH.

Roland

S. Aguinaga wrote:
> Hello!
> 
> Got audio working off a second thread and I am able to 'stop' it while 
> it isRunning(), 
> but am I halting it gracefully, and what do I have to do to quit the app 
> while thread is running?
> A pushbutton is used to  start the audio thread, then it is pressed 
> again to Stop it.
> 
>     connect(newstartButton, SIGNAL(clicked()), this,
>     SLOT(startAudioThread()));
>     connect(quitButton , SIGNAL(clicked()), qApp, SLOT(quit())); // This
>     doesn't work cleanly
> 
> 
> The slot: I use t_stop bool flag to check if the button was pressed to 
> stop the the thread.
> If the thread is started, I change the txt of the button to read "Stop 
> Thread"
> 
>     void AudKeyWidget::startAudioThread()
>     {
>     if (t_stop) { 
>     printf("Thread is running\n");
>     stopAudio();
>     }
>     else {
>     thread = new cAudioThread(this);
>     thread->start();
>     t_stop = !t_stop;
>     if(t_stop)
>     newstartButton->setText("Stop Thread");
>     }
>     }
> 
> If we are stopping the thread, then I handle this using function 
> stopAudio().
> 
>     void AudKeyWidget::stopAudio()
>     { printf("Stop Audio\n");
>     if (t_stop && thread->isRunning()) {
>     thread->terminate();
>     delete thread;
>     t_stop = !t_stop;
>     }
>     }
> 
> 
> But using terminate() offers the proper way to halt the thread? & reset 
> things?
> now my Continuous audio thread (caudiothread), some of this code was 
> taken from the 
> mandelbrot example.
> 
>     cAudioThread::cAudioThread(QObject *parent)
>         : QThread(parent)
>     {
>         printf("-- cAudioThread(QObject *parent) : QThead(parent) ...\n");
>         restart = false;
>         abort = false;
> 
>     }
> 
>     cAudioThread::~cAudioThread()
>     {
>         mutex.lock();
>         abort = true;
>         condition.wakeOne();
>         mutex.unlock();
> 
>         wait(); // Does is make sense to use this if we will almost 
>     // always halt the thread rather wait for it to end?
> 
>     }
>     void cAudioThread::run()
>     {
>     printf("-- Independent thread, run() function started\n");
>     forever { 
>     // ++++++++++++++++++ continuous audio (tone) ++++++++++++++++++ //
>     blah, blah, blah
>     // --------------------------- end continuous audio
>     mutex.lock();
>     if (!restart)
>     condition.wait(&mutex);
>     restart = false;
>     mutex.unlock();
>     }// ends forever
> 
>     }
> 
> 
> Finally the caudiothread.h, I would be interested in how to quit while 
> running and if stopAudio offers a clean approach to halt the thread.
> 
>         class cAudioThread : public QThread
> 
>         {
> 
>             Q_OBJECT
> 
> 
>         public:
> 
>             cAudioThread(QObject *parent = 0);
> 
>             ~cAudioThread();
> 
> 
>           void playAudio( int );
> 
> 
>         protected:
> 
>             void run();
> 
> 
>         private:
> 
> 
>             QMutex mutex;
> 
>             QWaitCondition condition;
> 
>             bool restart;
> 
>             bool abort;
> 
> 
>         };
> 
> 
> 
>     // Salvador Aguinaga
> 
>     // Northwestern Univeristy
> 
> 
> ------------------------------------------------------------------------
> *From:* S. Aguinaga <sa_jr at yahoo.com>
> *To:* Qt Interest <Qt-interest at trolltech.com>
> *Sent:* Tue, February 2, 2010 7:15:52 AM
> *Subject:* Re: [Qt-interest] bloody ungraspable control of my pusbutton
> 
> Thank you Ross, Amulya, and Jeroen for your responses and suggestions.
> I will work on this and report back and post my solution ( for others ).
> 
> // Sal 
> 
> ------------------------------------------------------------------------
> *From:* S. Aguinaga <sa_jr at yahoo.com>
> *To:* Qt Interest <Qt-interest at trolltech.com>
> *Sent:* Mon, February 1, 2010 10:31:04 PM
> *Subject:* Re: [Qt-interest] bloody ungraspable control of my pusbutton
> 
> I left out that that my application is a linux application an I am running 
> qt 4.6
> 
> The audio access is based on alsa, I'm wondering why this method becomes
> so strong and focused that even trying to quit the app does not responds.
> Does this pieces of code need an interrupt of some type?  What other 
> instances
> cause such a similar behavior?
> 
> I'm sure that there is some method that can address this issue.  If you 
> want me
> to post the entire qt code, I can.
> 
> Thanks in advance.
> 
> // Sal 
> 
> ------------------------------------------------------------------------
> *From:* S. Aguinaga <sa_jr at yahoo.com>
> *To:* Qt Interest <Qt-interest at trolltech.com>
> *Sent:* Mon, February 1, 2010 10:21:56 PM
> *Subject:* bloody ungraspable control of my pusbutton
> 
> Dear Fellows,
> 
> I have a question for the best of you.
> 
> I have a button that initiates a tone stimulus using my audio device.
> This stimulus is meant to be continuous until the pushbutton is toggled,
> but what is happening is that once my code goes into the audio loop it 
> never allows control back to my pushbutton, in other words, I can't 
> toggle it
> and right now the only way out is to go to the terminal and do control-C.
> 
> here is the loop:
> 
> while ( contToneButton->isChecked() ) {
>         chk_msg();
>         c = (int) floor((1 + oct0) * ncue / 2);
>         cue(c);
>         (void) ar_io_cur_seg(dvid);
> };
> 
> have any of you come across something like this an do you mind sharing 
> your methods?
> 
> 
> Thank you
> 
> // Sal Aguinaga
> // Northwestern University
> 
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Qt-interest mailing list
> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest