Passing slot as parameter in function to connect to a signal

[JonexElectronic]

Hi,
I'm trying to connect a signal to a slot that I have received as const char* in my function but I'm doing something wrong.
This is the function that create a QPushButton and connect the signal click to my slot.

void addPushButtonInTableCell(U2bYTES row, U2bYTES column, U2bYTES numberToPushButton, QTableWidget * pTableWidget , QWidget* parent, QString ruta, const char* slot)
{
	QWidget *pWidget = new QPushButton(QString::number(numberToPushButton),parent);	
...
	QObject::connect(pWidget, SIGNAL(clicked()),parent, SLOT(slot));
}

them I invoke the function.

addPushButtonInTableCell(0,15,pQ->u.cue.n, tableWidget , pMW->options, ":/ui/recursos/ExtrasInsert.png","on_pushButton_newJump_clicked()");

It compile and give to me next warning message

warning: unused parameter ‘slot’ [-Wunused-parameter]
 void addPushButtonInTableCell(U2bYTES row, U2bYTES column, U2bYTES numberToPushButton, QTableWidget * pTableWidget , QWidget* parent, QString ruta, const char* slot)
                                                                                                                                                                 ^

when I execute it i received this message on qdebug

QObject::connect: Parentheses expected, slot optionstouch::slot in ../motor/lib.cpp:26206
QObject::connect:  (receiver name: 'optionstouch')

[J.Hilk]

@JonexElectronic I'm hesitant to help, because your approach smells like a fundamental problem in the setup of what you want to do.

anyway, your slot function argument is already a const char*, so no need to make it one, with the SLOT macro.

-> QObject::connect(pWidget, SIGNAL(clicked()),parent,slot);

[raven-worx]

@J-Hilk said in Passing slot as parameter in function to connect to a signal:

so no need to make it one, with the SLOT macro

the SLOT macro does a little bit more than just casting it to a const char*

but i agree, connecting a slot on a signal invocation doesnt seem right

[JonexElectronic]

@J-Hilk @raven-worx If I do not use SLOT I received the next qDebug message.

QObject::connect: Use the SLOT or SIGNAL macro to connect optionstouch::on_pushButton_newJump_clicked()

I do not understand what do you mean with "because your approach smells like a fundamental problem in the setup of what you want to do."
I just create a QPushButton and insert it in QTableWidget and I want to execute the funtion that I passed in my slot when the button is clicked.
how should I do that? Is there a better way to do it?

[J.Hilk]

@raven-worx said in Passing slot as parameter in function to connect to a signal:

the SLOT macro does a little bit more than just casting it to a const char*

really? 🤔 Probably moc, when its running, right ?

I'm based mine purely on this:

Is there a better way to do it?

probably, but to be honest, I'm unsure, what exactly you want to do:
I want to execute the function that I passed in my slot when the button is clicked doesn't make much sense to me

[raven-worx]

@J-Hilk said in Passing slot as parameter in function to connect to a signal:

I'm based mine purely on this:

exactly, and it adds "1" as a prefix. which is then used by the meta-object instance for lookup of the method and check if its really a slot.

[JonexElectronic]

I have decided to change my funtion.

QWidget* addPushButtonInTableCell(U2bYTES row, U2bYTES column, U2bYTES numberToPushButton, QTableWidget * pTableWidget , QWidget* parent, QString ruta, const char* slot)
{
	QWidget *pWidget = new QPushButton(QString::number(numberToPushButton),parent);	
...
	return pWidget;
}

Invoke

QWidget* pWidget = addPushButtonInTableCell(0,15,pQ->u.cue.n, tableWidget , pMW->options, ":/ui/recursos/ExtrasInsert.png");
	QObject::connect(pWidget,SIGNAL(clicked()), pMW->options, SLOT(on_pushButton_newJump_clicked()));

It works fine.