Why is the copy constructor in this code never called?

[Jordan Stefanov]

Hi,

I have the following code:

class A
{
    public:
        A(){ cout << "A.ctor()" << endl; }
        // the others methods have similar couts
};

A f() { return A(); }

int main()
{
    f();
}

When I run it, I see:

A.ctor()
A.dector()

which is fine with me.
But when I change the code to:

int main()
{
    A a = f();
}

I see the same output o.O
Why is the copy constructor of A never called, and which dector do I call in the end - the one of the temporary object, or the the one of the variable 'a'?

[kbw]

http://en.wikipedia.org/wiki/Return_value_optimization

[Jordan Stefanov]

Thanks : )