auto_ptr (shared_ptr as well) try to make their use as transparent as possible; that is, ideally, you should not be able to tell a difference whether you're using an auto_ptr or a real pointer to an object. Consider:
class MyClass
{
public:
void foo() { }
};
MyClass* p = new MyClass;
auto_ptr<MyClass> ap(new MyClassp);
p->foo(); // No notational difference in using real
ap->foo(); // pointers and auto_ptrs
When you try to invoke a member function through a pointer-to-member, there is a difference, as auto_ptr obviously doesn't implement op->*():
void (MyClass::*memfun)() = &MyClass::foo;
(p->*memfun)(); // OK
(ap->*memfun)(); // Error op->*() missing
(ap.get()->*memfun)(); // OK
Why is there no support for op->*() in auto_ptr and how would one implement it (I've experimented for some time, but ultimately gave up).