help with https://doc.qt.io/qt-5/qthread.html

micha_eleric

void MyObject::startWorkInAThread()
{
    WorkerThread *workerThread = new WorkerThread(this);
    connect(workerThread, &WorkerThread::resultReady, this, &MyObject::handleResults);
    connect(workerThread, &WorkerThread::finished, workerThread, &QObject::deleteLater);
    workerThread->start();
}

o have tried : QThread() and :QObject

CThreadController.h file

#include "CControls.h"
#include <QObject>
#include <QThread>
#include <iostream>

class CThreadController : public QObject
{
    Q_OBJECT
    CNC::CControls *controlsThread;
public:
    // constructor
    CThreadController();
    // destructor
    ~CThreadController();

    //
    void startThreads();
};

CThreadController.cpp file

#include "CThreadController.h"
#include "CControls.h"

CThreadController::CThreadController() : QThread()
{
}

CThreadController::~CThreadController()
{
    controlsThread->quit();
    controlsThread->wait();
}

void CThreadController::startThreads()
{
    std::cout << "startThreads() begin\n" << std::flush;

    controlsThread = new CNC::CControls(this);
    connect(controlsThread, &QThread::finished, controlsThread, &QObject::deleteLater);
    controlsThread->start();

    std::cout << "startThreads() end\n" << std::flush;
}

CControls.h file

#include <QObject>
#include <QThread>

namespace CNC
{
    class CControls : public QThread
    {
        Q_OBJECT
    public:
        //CControls();

        void run() override;
    };
}

this is error i get when CThreadController inherits from QThread or QObject

error: no matching function for call to ‘CNC::CControls::CControls(CThreadController*)’
   18 |     controlsThread = new CNC::CControl

i commented out constructor, so it should default to inherited constructor

what is in WorkerThread constructor and what does it inherit from?

WorkerThread *workerThread = new WorkerThread(this);

jsulm

@micha_eleric said in help with https://doc.qt.io/qt-5/qthread.html:

controlsThread = new CNC::CControls(this);

You are passing CThreadController* to the constructor, so what do you expect if CControls does not have such a constructor?

"what is in WorkerThread constructor and what does it inherit from?" - how should we know? You did not show the code for WorkerThread...

micha_eleric

@jsulm https://doc.qt.io/qt-5/qthread.html

micha_eleric

@jsulm " - how should we know? You did not show the code for WorkerThread.." that is the question about https://forum.qt.io/topic/113070/qt-code-of-conduct

i keep looking at webpage, trying to figure out the answer.

jsulm

@micha_eleric said in help with https://doc.qt.io/qt-5/qthread.html:

that is the question about https://forum.qt.io/topic/113070/qt-code-of-conduct

Not sure what you mean.
I know the path to QThread documentation. I already gave you the answer to your question: there is no such constructor CNC::CControls::CControls(CThreadController*)! Please take a look at the code YOU posted:

namespace CNC
{
    class CControls : public QThread
    {
        Q_OBJECT
    public:
        //CControls();

        void run() override;
    };
}

What constructor does this class have and what constructor are you trying to call?

JKSH

@micha_eleric said in help with https://doc.qt.io/qt-5/qthread.html:

i commented out constructor, so it should default to inherited constructor

No, constructors are not inherited like that. You must implement the relevant constructor.

micha_eleric

void MyObject::startWorkInAThread()
{
    WorkerThread *workerThread = new WorkerThread(this);
    connect(workerThread, &WorkerThread::resultReady, this, &MyObject::handleResults);
    connect(workerThread, &WorkerThread::finished, workerThread, &QObject::deleteLater);
    workerThread->start();
}

what is the WorkerThread constructor suppose to do?
this is not my code, so i can not show what WorkerThread constructor does.
can someone tell me what WorkerThread constructor from https://doc.qt.io/qt-6/qthread.html is suppose to do?

JonB

@micha_eleric
The constructor creates a QThread with MyObject instance as its parent. It is explained in that example, not sure what you are wanting to ask.

micha_eleric

@JonB

class WorkerThread : public QThread
{
    Q_OBJECT
    void run() override {
        QString result;
        /* ... here is the expensive or blocking operation ... */
        emit resultReady(result);
    }
signals:
    void resultReady(const QString &s);
};

no constructor stated on https://doc.qt.io/qt-6/qthread.html

void MyObject::startWorkInAThread()
{
    WorkerThread *workerThread = new WorkerThread(this);
}

results in

485: error: no matching function for call to ‘WorkerThread(MyObject*)’

JonB

@micha_eleric said in help with https://doc.qt.io/qt-5/qthread.html:

no constructor stated on https://doc.qt.io/qt-6/qthread.html

?
The base constructor is QThread::QThread(QObject *parent = nullptr). So what is the definition of class MyObject? Or, perhaps guessing from the error message, have you declared the constructor for WorkerThread? I'm not sure you have. @JKSH answered earlier

i commented out constructor, so it should default to inherited constructor

No, constructors are not inherited like that. You must implement the relevant constructor.

micha_eleric

@JonB said in help with https://doc.qt.io/qt-5/qthread.html:

@micha_eleric said in help with https://doc.qt.io/qt-5/qthread.html:

no constructor stated on https://doc.qt.io/qt-6/qthread.html

?
The base constructor is QThread::QThread(QObject *parent = nullptr). So what is the definition of class MyObject? Or, perhaps guessing from the error message, have you declared the constructor for WorkerThread? I'm not sure you have. @JKSH answered earlier

i commented out constructor, so it should default to inherited constructor

No, constructors are not inherited like that. You must implement the relevant constructor.

i have no clue what the constructor is suppose to be for WorkerThread, sence the webpage does not say, and i keep asking what it is suppose to be

JonB

@micha_eleric
You should do, because it is the same as the base class one:

public: 
    explicit WorkerThread(QObject *parent = 0) :
        QThread(parent)
    {
    }

micha_eleric

@JonB ty. i was wandering about that based on other pages, but not sure