Overloading pointer-to-member function

[shenli]

Dear All,

I have encountered an unexpected result when overloading the pointer-to-member function. In the following code:

#include <iostream>

using namespace std;

class X {
public:
void f() { cerr << "f() called!" << endl; }
void operator() () { cerr << "operator() called!" << endl; }
X operator->* (void (X::*pmf)()) { cerr << "operator->* called!" << endl; return *this; }
} x;

int main (int argc, char **argv) {
void (X::*p)() = &X::f; ((&x)->*p)();
return 0;
}

I would have expected the output:

operator->* called!
operator() called!

But instead I get the output

f() called!

which indicates to me that the overloading was not succesfull.

Could someone kindly point out what mistake I am making here?

Many thanks,
Shen

[hamsterman]

You would have gotten "operator() called!" is your code was "x()" and "operator->* called!" if it was "x->*p".
Here the left argument of ->* is X* and not X.

[shenli]

Thank you very much for your quick and insightful response.

Is there a possibility to overload ->* in such a way that

((&x)->*p)();

calls operator->*?

Many thanks.
Shen

[hamsterman]

It is possible to define ->* outside a class (so that the left argument is X*) but C++ doesn't allow to overload operators when both arguments are pointers, so no (unless you overload & too).

[shenli]

Thanks a lot! That answers my question.