How to solve the problem of inherits multi super classes

[nicker player]

//DEFINED THE INTERFACE OF THE CLASS
class ICallback{
private:
		ICallback * m_callback;
public:
	void setCallback(ICallback * ptr){
		m_callback = ptr;
	}
	ICallback * getCallback(){
		return m_callback;
	}
	virtual void callback(void * ptr){
		...
	}
	
	QString dosomething(){
		...
		//return the marked string of the ICallback 
		...
	}
}

//
class ClassA :public QPushButton,public ICallback{
Q_OBJECT
public:
	virtual void callback(void * ptr) override{
		...
		//do some thing marked the ClassA for dosomething() could get a value of the ClassA
		...
		ICallback * t_callback = getCallback();
		//here is the problem,t_callback->callback called but the pointer of this seemed cant find the real object
		t_callback->callback(this);
	}
	
}

class ClassB :public QWidget,public ICallback{
Q_OBJECT
public:
	virtual void callback(void * ptr) override{
		...
		QObject * t_obj = (QObject*)ptr;
		// this code could run normally
		t_obj->objectName();
		//
		ClassA * t_classa = (ClassA*)ptr;
		
		//this is the problem,the t_classa
		t_classa->dosomething();
		
	}
}


//usage :

ClassA * ptrA = new ClassA();

ClassB * ptrB = new ClassB();

ptrA->setCallback(ptrB);
//here is the problem, the ClassB callback(){} could not run the code t_classa->dosomething(),caused the pointer 
ptrA->callback();

[Christian Ehrlicher]

Can you please describe your problem and what you're trying to achieve. Your code above does not tell me anything.

[nicker player]

@Christian-Ehrlicher

class ClassB
virtual void callback(void * ptr) override{
                  //this is the problem,the t_classa dosomething() dosnt work. I trans the pointer of the void  to the ClassA,But it failed
		t_classa->dosomething();
}

[wrosecrans]

@nicker-player "failed" how? You aren't actually explaining what problem you are having, or what you are trying to accomplish.

[J.Hilk]

@nicker-player first of all, for the love of the c++ gods, don't use c-style casts, use dynamic cast here, because I'm betting my last pair of underwear that you did not disable RTTI. So it is available to you.

post what you actually do in "do something"

also I fail to see your initialisation of ICallback where do you do that ?

[SimonSchroeder]

Your callback inside ClassB casts the pointer ptr it receives to ClassA. For a callback I would expect it to be called with itself as parameter. So, if ptr is of type ClassB you are not allowed to cast it to ClassA because those are not related at all. Is ptr of type ClassA in your case?

[Hitul]

This post is deleted!

[Kent-Dorfman]

How to solve the problem of inherits multi super classes

In computer science texts this is called the "diamond problem". There are countless online discussions about it. It's not specifically a Qt problem, but a design paradigm challenge.