BlockingQueuedConnection is not working it is leading to deadlock condition.

[us@12]

Hi everyone,
I am uing Qt:: BlockingQueuedConnection in the connect option like below, but it going to deadlock state when i use this please help me in this issue soon am a newbie to Qt.. Here is my code

connect (this, SIGNAL(moduleDatarcvd(int)), this, SLOT(ShowModuleSimWnd(int)),Qt::BlockingQueuedConnection);

connect (this, SIGNAL(moduleDatarcvd(int)), this, SLOT(ShowModuleSimWnd(int)),Qt::BlockingQueuedConnection);

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here i am waiting for a signal to come when my ShowmoduleSimWnd method is called. please tell me an alternative that wath i can use.and for this blocking of my ui is happening. please help me

[ChrisW67]

As the friendly manual says:

This connection type should only be used where the emitter and receiver are in different threads. Note: Violating this rule can cause your application to deadlock.

Are your sender and receiver in separate threads?

[us@12]

ya exactly both the emitter and receiver are in different thread...

[Lesiok]

...here i am waiting for a signal to come when my ShowmoduleSimWnd method is called...

Please show a code. I think that a problem is "i am waiting".

[us@12]

void VSDPM_CDT::DisplaySimWnd(int nModule)
{
	emit moduleDatarcvd(nModule);
}

void VSDPM_CDT::DisplaySimWnd(int nModule)
{
	emit moduleDatarcvd(nModule);
}

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Here i am emitting a signal i.e n module and at receiver side:

connect (this, SIGNAL(moduleDatarcvd(int)), this, SLOT(ShowModuleSimWnd(int)),Qt::BlockingQueuedConnection);

connect (this, SIGNAL(moduleDatarcvd(int)), this, SLOT(ShowModuleSimWnd(int)),Qt::BlockingQueuedConnection);

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and my ShowmoduleSimWnd is a method which will be called when it is received a signal i.e

void VSDPM_CDT::ShowModuleSimWnd(int nModule)
{
	if(nModule == 0)
	{
		OnClickCanSimulation();
	}
	else if(nModule == 1)
	{
		OnClickLinSimulation();
	}
	else if(nModule == 2)
	{
		OnClickADCSimulation();
	}
	else if(nModule == 3)
	{
		OnClickDIOSimulation();
	}
	else if(nModule == 4)
	{
		OnClickPWMSimulation();
	}
	else if(nModule == 5)
	{
		ShowLogMessage("test","Inside module");
		OnClickTCPIPSimulation();
	}
	else if(nModule == 6)
	{
		OnClickBTSimulation();
	}
}

void VSDPM_CDT::ShowModuleSimWnd(int nModule)
{
	if(nModule == 0)
	{
		OnClickCanSimulation();
	}
	else if(nModule == 1)
	{
		OnClickLinSimulation();
	}
	else if(nModule == 2)
	{
		OnClickADCSimulation();
	}
	else if(nModule == 3)
	{
		OnClickDIOSimulation();
	}
	else if(nModule == 4)
	{
		OnClickPWMSimulation();
	}
	else if(nModule == 5)
	{
		ShowLogMessage("test","Inside module");
		OnClickTCPIPSimulation();
	}
	else if(nModule == 6)
	{
		OnClickBTSimulation();
	}
}

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in lin if(nModule == 5) i am getting a problem. Actually i am blocking the queue here to wait for a signal to come. please help me in this scenario

[Lesiok]

But it is SLOT ! You are entering ShowModuleSimWnd(int nModule) as reaction on blocking signal. You can not pick up the next signal before the end of the previous operation.

[us@12]

Ya but how can i solve this problem i have to block the queue until my method get finished.. how my approach should be for this.

[Lesiok]

You can not wait that someone will come if you closed the door. You have to design the logic of the system from scratch.