Use Qt thread correctly

[Galilio]

At a class where I have the object "CAgilentLan"
Calls I write in the contructor the following:

//CAgilentLan* m_pvAgilentWorker; 
m_pvWorkerThread = new QThread();
m_pvAgilentWorker = new CAgilentLan(settings_l.strfuGetIP_DSO(), 500, settings_l.bofuGetSimulate());
m_pvAgilentWorker->moveToThread(m_pvWorkerThread);
connect(m_pvWorkerThread, &QThread::started, m_pvAgilentWorker, &CAgilentLan::agilentStart);
   
connect(m_pvWorkerThread, &QThread::finished, m_pvWorkerThread, &QThread::deleteLater);
connect(m_pvWorkerThread, &QThread::finished, m_pvWorkerThread, &CAgilentLan::deleteLater);
m_pvWorkerThread->start();

This is the error message:

ASSERT failure in QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread. Current thread 4c19f68. Receiver '' (of type 'QNativeSocketEngine') was created in thread 4c582e0", file kernel\qcoreapplication.cpp, line 541

[corruptedsyntax]

@jsulm

QByteArray CAgilentLan::GetLastResponse(void)
{
    QMutexLocker(m_MtxResponse);
    return m_ByteArrayRead;
}

Won't that temporary QMutexLocker need a name? Otherwise it will be deconstructed as a temporary object at the end of the first statement and the return won't be locked properly.

[jsulm]

@corruptedsyntax Sure, thanks for pointing that out :-)

QByteArray CAgilentLan::GetLastResponse(void)
{
    QMutexLocker mutexLocker(m_MtxResponse);
    return m_ByteArrayRead;
}

[Galilio]

@jsulm
Hi,
So is correct:

QByteArray CAgilentLan::GetLastResponse(void)
{
    QMutexLocker mutexLocker(&m_MtxResponse);
    return m_ByteArrayRead;
}

[jsulm]

@Galilio yes

[Galilio]

Hi,
How can I avoid this error?

[Galilio]

@jsulm
Problem occurs when the application is exited.
The Destructor is then called, which looks like this:

CAgilentLan::~CAgilentLan()
{
	this->Close(GetiTimeOutClose());

	if (this->Execute("DeleteObject", 0, 0, 0) != enRspOK)
	{
		throw(QString("Error AgilentLan.CPP/Destructor TcpSocket Delete memory error"));
	}
}

And right here is the problem:

GetTcpSocket()->disconnectFromHost();

[jsulm]

@Galilio What error? What problem? Can you be more precise?
You should not throw exceptions from destructors.

[Galilio]

@jsulm
The TcpSocket connection can not be closed
Error is:

ASSERT failure in QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread. Current thread dc02d0. Receiver '' (of type 'QNativeSocketEngine') was created in thread 4912418", file kernel\qcoreapplication.cpp, line 541

[jsulm]

@Galilio You are doing something wrong with your threads

[Galilio]

@jsulm
Yes but what?
My QThread looks like this:

m_pvWorkerThread = new QThread();
m_pvAgilentWorker = new CAgilentLan(settings_l.strfuGetIP_DSO(), 500, settings_l.bofuGetSimulate());
m_pvAgilentWorker->moveToThread(m_pvWorkerThread);
connect(m_pvWorkerThread, &QThread::started, m_pvAgilentWorker, &CAgilentLan::agilentStart);
   
connect(m_pvWorkerThread, &QThread::finished, m_pvWorkerThread, &QThread::deleteLater);
connect(m_pvWorkerThread, &QThread::finished, m_pvWorkerThread, &CAgilentLan::deleteLater);
m_pvWorkerThread->start();

[jsulm]

@Galilio Sorry, currently I have no time to analyse your code.
You should read: https://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/