We all know members specified `protected` from a base class can only be accessed from a derived class own instance. This is a feature from the Standard, and this has been discussed on Stack Overflow multiple times:

 - [Cannot access protected member of another instance from derived type&#39;s scope
](https://stackoverflow.com/q/45146025/5470596 &quot;a similar question on Stack Overflow&quot;);
 - [Why can&#39;t my object access protected members of another object defined in common base class?](https://stackoverflow.com/q/17717027/5470596 &quot;a similar question on Stack Overflow&quot;)
 - And others.

But it seems possible to walk around this restriction with member pointers, as user chtz [has shown me](https://stackoverflow.com/a/49538355/5470596 &quot;their answer to a related question&quot;):

    struct Base { protected: int value; };
    struct Derived : Base
    {
        void f(Base const&amp; other)
        {
            //int n = other.value; // error: &#39;int Base::value&#39; is protected within this context
            int n = other.*(&amp;Derived::value); // ok??? why?
            (void) n;
        }
    };

[Live demo on coliru](http://coliru.stacked-crooked.com/a/7680e07f219a73a7 &quot;(external)&quot;)

Why is this possible, is it a wanted feature or a glitch somewhere in the implementation or the wording of the Standard?

---

From comments emerged another question: [if `Derived::f` is called with an actual `Base`](http://coliru.stacked-crooked.com/a/185e06f44865b243), is it undefined behaviour?

All Member Pointers Solutions on Gang of Coders

Total of 1 Member Pointers Solutions

Access to protected member through member-pointer: is it a hack?