auto_ptr assignment

[Freon]

Does anybody know why auto_ptr transfers pointer ownership on assignment instead of making assignment and copy ctor unavailable?

[helios]

So you can do this?
T obj=*p;

[Freon]

No, that's invoking assignment of type T (assuming auto_ptr<T> p(new T); T obj = *p;)

[helios]

Oh, then your question is why you can assign an auto_ptr to another at all?
Well, a pointer that can't be copied isn't very useful. It would be no different than an object created on the stack.

[firedraco]

Because you might want to transfer the assignment like this maybe:

std::auto_ptr<int> foo(int data) {
    return std::auto_ptr<int> (new int(data));
}

int main() {
    std::auto_ptr<int> ptr(NULL);
    ptr = foo(25); //need = on here
    //...
}