How to connect a custom message lambda

IknowQT

	this->connect(cGlobalParam::Communicator()->worker, QOverload<Standard_MeasureDataReceive*>::of(&TcpClientThreadDoWork::Signal_MeasureDataReceive),
		[=](Standard_MeasureDataReceive* data)
		{

		});

class TcpClientThreadDoWork : public QObject
{
public:
signals:
    void Signal_MeasureDataReceive(Standard_MeasureDataReceive* e);
};

There is no error in the code itself, but an error occurs when compiling.
What is the cause of the link error?

오류 LNK2019 "public: void __cdecl TcpClientThreadDoWork::Signal_MeasureDataReceive(class Standard_MeasureDataReceive *)" (?Signal_MeasureDataReceive@TcpClientThreadDoWork@@QEAAXPEAVStandard_MeasureDataReceive@@@Z)"public: virtual void __cdecl wStandardCurve::Initialize(void)" (?Initialize@wStandardCurve@@UEAAXXZ)
MainWidget D:\ProgramSrc\POP\MainWidget\wStandardCurve.obj 1
오류 LNK2001 확인할 수 없는 외부 기호 "public: static struct QMetaObject const TcpClientThreadDoWork::staticMetaObject" (?staticMetaObject@TcpClientThreadDoWork@@2UQMetaObject@@B) MainWidget D:\ProgramSrc\POP\MainWidget\wStandardCurve.obj 1
오류 LNK1120 MainWidget D:\ProgramSrc\POP\Depoly_Exec\debug\MainWidget.exe 1

IknowQT

@IknowQT

	this->connect(cGlobalParam::Communicator()->worker, SIGNAL(Signal_MeasureDataReceive(Standard_MeasureDataReceive)),
		this, SLOT(Communicator_Event_MeasureDataReceive(Standard_MeasureDataReceive)));

If you declare and use it like this, it works normally.

jsulm

@IknowQT Would be goog if you would translate errors!

IknowQT

@jsulm said in How to connect a custom message lambda:

Would be goog if you would translate errors!

It is marked as an unresolved external symbol.
That's it.

J.Hilk

@IknowQT did you forward declare Standard_MeasureDataReceive and forgot to include the header?

IknowQT

@J-Hilk said in How to connect a custom message lambda:

Standard_MeasureDataReceive

has been declared. If it is not declared, I think there must have been a problem when it was used as a commonly used connect function, not a lambda function.

J.Hilk

@IknowQT said in How to connect a custom message lambda:

I think there must have been a problem when it was used as a commonly used connect function

if you're using Qt5 connect syntax yes, with the Qt4 one above, not necessarily (straight away)

KroMignon

@IknowQT said in How to connect a custom message lambda:

has been declared. If it is not declared, I think there must have been a problem when it was used as a commonly used connect function, not a lambda function.

No necessary, when using SLOT() and SIGNAL() for the connect, there is no check done during compilation, only on runtime.
signal / slot validity check on compilation is only done with new connection syntax.

IknowQT

@KroMignon
@J-Hilk

this->connect(cGlobalParam::Communicator()->worker, SIGNAL(Signal_MeasureDataReceive(Standard_MeasureDataReceive)),
		this, SLOT(Communicator_Event_MeasureDataReceive(Standard_MeasureDataReceive)));	

void wStandardCurve::Communicator_Event_MeasureDataReceive(const Standard_MeasureDataReceive data)
{
	emit UserDefine_ReceiveData(data);
}

this->connect(this, &wStandardCurve::UserDefine_ReceiveData, [&](const Standard_MeasureDataReceive data)
{
	rcvData = data;
});

Communicator_Event_MeasureDataReceive -> UserDefine_ReceiveData -> lamba Func

So what's the problem?
I did one test. I generated singnal one more time and connected it with a lambda. It connects normally.

The goal I want to use is to use the signal without going through it once more.

jsulm

@IknowQT said in How to connect a custom message lambda:

The goal I want to use is to use the signal without going through it once more

You can connect signals with other signals, not only signals with slots...

IknowQT

@jsulm

This is what I tested and shared.
I don't know what is causing the link error in the lambda.

KroMignon

@IknowQT said in How to connect a custom message lambda:

So what's the problem?
I did one test. I generated singnal one more time and connected it with a lambda. It connects normally.

I am a little bit lost, is the signal signature Signal_MeasureDataReceive(Standard_MeasureDataReceive) or Signal_MeasureDataReceive(Standard_MeasureDataReceive*) ?

IknowQT

@KroMignon said in How to connect a custom message lambda:

I am a little bit lost, is the signal signature Signal_MeasureDataReceive(Standard_MeasureDataReceive) or Signal_MeasureDataReceive(Standard_MeasureDataReceive*) ?

To be exact, Signal_MeasureDataReceive(Standard_MeasureDataReceive).

J.Hilk

@IknowQT said in How to connect a custom message lambda:

@KroMignon said in How to connect a custom message lambda:

I am a little bit lost, is the signal signature Signal_MeasureDataReceive(Standard_MeasureDataReceive) or Signal_MeasureDataReceive(Standard_MeasureDataReceive*) ?

To be exact, Signal_MeasureDataReceive(Standard_MeasureDataReceive).

why do you tell the QOverload and the lambda argument that its a pointer?

QOverload<Standard_MeasureDataReceive*>::of(&TcpClientThreadDoWork::Signal_MeasureDataReceive),
		[=](Standard_MeasureDataReceive* data)

IknowQT

@J-Hilk

Declaring a pointer class is just a test case.
The same lnk error occurs for pointer classes and regular classes.

J.Hilk

@IknowQT
Can you even use Lambdas ?

what's your Qt version, c++ Version and compiler?

IknowQT

@J-Hilk

C:\Qt\5.15.2\msvc2019_64
That is all.