howto restric a method to being absolutely constant

[ssouffri]

I disagree with your assertion completely. A const member function cannot change the state of objects that it has a pointer to even if the pointer is non-const (at least not without some hacking).

I wish you were right but the code below compiles without errors or warnings.

class NotConstObject {
private:
        int i;
public:
        void nonConstMember(){
                i=0;
        }
};

class ConstObject{
private:
        NotConstObject *nco;
public:
        ConstObject(NotConstObject *nco): nco(nco){
        }

        void operator()() const {
                nco->nonConstMember();
        }
};


main(void){
 NotConstObject nco;
 const ConstObject o(&nco);
 o();
 return 0;
}

The reason why your code fails is because of the following line where a class attribute is changed.

theCollector.insert(rhs[last]);

A const function can call non-const functions on input arguments if the input arguments aren't const. If a const function receives a non-const array as an input it can modify the input array but cannot modify the state of the object that it belongs to. Understand?

Yes i do but that's not my problem. My problem is simply that

nco->nonConstMember();

does not cause any compiler errors.

My compiler is "g++ (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291]". Maybe your compiler will refuse to compile the above code in which case it's an interpretation difference issue. If so, which compiler complies with which C++ standard? And which one makes more sense?