How to correctly do operator overloading in C++/CLI?

Question

In my class, I have something like this:

public ref class Something {
public:
    // some methods

    operator double();
}

Something wraps something from a third-party DLL which has exactly the same operator double() in its header. The compiler now complains about an unresolved token: MyNamespace.Something::op_Implicit

How do I have to define this in my implementation?

I tried the following three which did not work:

• double Something::op_Implicit() - "op_Implicit is not a member"
• static double Something::op_Implicit(Something^ s)- "op_Implicit is not a member"
• operator Something::double() {...} - tons of syntax errors

Answer 1

Easier to write it inline:

public ref class Something {
    double yadayada;
public:
    operator double() { return yadayada; }
};

If you don't then the proper syntax is:

Something::operator double() {
    return yadayada;
}

Which is all okay for usage from C++/CLI code, but if you want to expose the conversion function to other languages then you should declare it static:

public ref class Something {
    double yadayada;
public:
    static operator double(Something^ arg) {
        return arg->yadayada;
    }
};

Prefix the explicit keyword to avoid accidental conversion and force the client code to use a cast.