New syntax connect not triggering the slot

[Puppy Bear]

Hi, I'm trying to use new syntax of connect ,
but somehow I've found out it couldn't trigger the slot properly while old connect method can.
However,
I've checked parameters and Q_OBJECT inheration, connect both return true.

The slot still couldn't be triggered after emit the signal.
(qdebug in slot not printing)

Am I writing any wrong code?

The code is like
//all classes inherit q_object

bms.h

class XLBmsProtocolPrivate;
class XLBMSPROTOCOL_SHARED XLBmsProtocol : public QObject
{
	Q_OBJECT
public:
	XLBmsProtocol(QObject *parent = Q_NULLPTR);
	~XLBmsProtocol();
public:
Q_SIGNAL void sigDCcmd0x65(const int);
}

bms.cpp

XLBmsProtocol::XLBmsProtocol(QObject *parent)
	: QObject(parent)
	, d_ptr(new XLBmsProtocolPrivate(this))
{
	QThread *m_pThread = new QThread;
	this->moveToThread(m_pThread);
	m_pThread->start();
}

void XLBmsProtocol::SlotSendSig(const int num)
{
qDebug() << "emit signal"; //always being printed.
emit sigDCcmd0x65(num);
}

DCProtocolInitFrm.h

class DCProtocolInitFrm : public DCAbstractProtocol
{
	Q_OBJECT
public:
	explicit DCProtocolInitFrm(DCProtocolInitFrmPrivate *dd, QWidget *parent = Q_NULLPTR);

protected:
void InitConnect();
void DisConnect();

protected
Q_SLOT virtual void slotDCcmd0x65(const int) Q_DECL_OVERRIDE;

private:
	Q_DISABLE_COPY(DCProtocolInitFrm)
	Q_DECLARE_PRIVATE(DCProtocolInitFrm)

DCProtocolInitFrm.cpp

void DCProtocolInitFrm::InitConnect()
{
auto tBmsPtr = MyApp->GetProcessPtr();

connect(tBmsPtr, SIGNAL(sigDCcmd0x65(const int)), this, SLOT(slotDCcmd0x65(const int)));  //this works perfectly

/*connect(tBmsPtr, &XLBmsProtocol::sigDCcmd0x65, this,
		&DCProtocolInitFrm::slotDCcmd0x65);*/ //while this function wasn't working at all.
}

Q_SLOT void DCProtocolInitFrm::slotDCcmd0x65(const int SkipSignal)
{
	Q_D(DCProtocolInitFrm);
        //print sth here, wasn't work under new syntax
}

[JonB]

@Puppy-Bear
Start with what class is the this in 3.cpp? And it's not helpful that your example uses class names like DCProtocolInitFrm while your example uses A & B, difficult to understand what is actually what.....

[Gojir4]

@Puppy-Bear said in New syntax connect not triggering the slot:

class C: public Q_OBJECT

Does this really compile ?

class C: public Q_OBJECT

It should be

class C: public QObject {
    Q_OBJECT
    // ... 
}

[JonB]

@Gojir4
Who knows, because the paste cannot be OP's real code, as classB:public A would be incorrect anyway.....

[J.Hilk]

also everything is supposed to be in cpp files, which moc does not parse without explicitly being told to do so.

[Puppy Bear]

Sorry for the inaccurate description, I've updated the code

[Puppy Bear]

@Gojir4 Sorry for the inaccurate description, the code is being updated and Q_object won't be a problem

[JonB]

@Puppy-Bear said in New syntax connect not triggering the slot:

The slot still couldn't be triggered after emit the signal.
(qdebug in slot not printing)

Start from:

connect(tBmsPtr, &XLBmsProtocol::sigDCcmd0x65,
        this, []() { qDebug("Signal emitted"); });

I also note your new code now shows you are using QThread, which you did not mention before. That means you will be using queued connections. Are you allowing the Qt event loop to run? [If the above connect() does not print anything, does it make any difference if you replace this with tBmsPtr?)