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maximus

Hi,

I've read the "Threading Basics":http://qt-project.org/doc/qt-5.0/qtcore/thread-basics.html

Before I did successfully do a thread by subclassing QThread and using run(), but I read this is not good use. My Thread needs to be permanent (lifetime of my application). I want to retrieve data from it at various time.

So now I want to implement this kind of Threa

JKSH

Hi,

That page is outdated. Those examples will be removed in the Qt 5.2 documentation.

You don't need to implement your own thread for your purpose. Just create a new QThread(). See the first example in the "QThread documentation":http://doc-snapshot.qt-project.org/qt5-stable/qthread.html#details

Also, see the "Multithreading Technologies in Qt":http://doc-snapshot.qt-project.org/qt5-stable/threads-technologies.html page for different ways to use threads in Qt -- subclassing QThread is ok for certain uses (but not for permanent threads like yours)

maximus

Thank you JKSH,

The example supplied worked perfectly for my needs, now I need to figure out how to exchange data from the controller and the worker, I think signal and slot will do the job just fine :)

@////////////////////////////////////////////////////////////////////////////////
/// CONSTRUCTOR
////////////////////////////////////////////////////////////////////////////////
DialogAnt::DialogAnt(QWidget *parent) :QDialog(parent),ui(new Ui::DialogAnt) {
ui->setupUi(this);

myHub = new Hub();  //cannot move object with a parent, so no parent and delete in destructor
myHub->moveToThread(&workerThread);

connect(myHub, SIGNAL(onStickFound()), this, SLOT(stickFound()) );
connect(myHub, SIGNAL(onStickFound()), myHub, SLOT(Start()) );

workerThread.start();
myHub->InitUSBStick();

}@

JKSH

[quote author="maximus" date="1384266474"]now I need to figure out how to exchange data from the controller and the worker, I think signal and slot will do the job just fine :)[/quote]Yes :) Use signals and slots to communicate both ways.

maximus

Hi again,

My thread is working fine but for terminating the thread, i'm facing some difficulties.

When I try to close my main GUI, the app becomes "not responding" trying to shut down the thread.
The only way I was able to shut it down is with workerThread.terminate() but then I get error at shutdown

My Thread is also running a thread inside it.
I tell it to stop with the flag "threadRunning" but still I get stop on the .wait in the main GUI.
Any idea on how to force the thread to stop without having a crash?

Thanks in advance!

[EDIT: The problem is in the children thread, it is not stopped before I stop it's parent thread, Stopping the children thread then the parent thread worked]

@#include "dialogant.h"
#include "ui_dialogant.h"
#include <QDebug>
#include "util.h"

////////////////////////////////////////////////////////////////////////////////
/// CONSTRUCTOR
////////////////////////////////////////////////////////////////////////////////
DialogAnt::DialogAnt(QWidget *parent) :QDialog(parent),ui(new Ui::DialogAnt) {
ui->setupUi(this);

myHub = new Hub();  //cannot move object with a parent, so no parent and delete in destructor
myHub->moveToThread(&workerThread);

connect(myHub, SIGNAL(onStickFound()), this, SLOT(stickFound()) );
connect(this, SIGNAL(pairHR()), myHub, SLOT(Start()) );
connect(myHub, SIGNAL(hrChanged(int)), this, SLOT(show_hr(int)) );

workerThread.start();
myHub->InitUSBStick();

}

////////////////////////////////////////////////////////////////////////////////
/// DESTRUCTOR
////////////////////////////////////////////////////////////////////////////////
DialogAnt::~DialogAnt() {
workerThread.quit();
workerThread.wait();
delete myHub;
delete ui;
}

////////////////////////////////////////////////////////////////////////////////
/// CloseEvent
////////////////////////////////////////////////////////////////////////////////
void DialogAnt::closeEvent(QCloseEvent *event) {

qDebug() << "CLOSING WINDOW";

// disconnect(myHub, SIGNAL(onStickFound()), this, SLOT(stickFound()) );
// disconnect(this, SIGNAL(pairHR()), myHub, SLOT(Start()) );
// disconnect(myHub, SIGNAL(hrChanged(int)), this, SLOT(show_hr(int)) );

// myHub->Close();

// workerThread.terminate(); works but shows error when app close
myHub->threadRunning = false;
myHub->Close();
workerThread.quit();
workerThread.wait();
}@