Pointers to static members of class

Question

From this reference:

(8.3.3/3) A pointer to member shall not point to a static member of a class (9.4), a member with reference type, or " cv void."

Why a pointer cannot point to a static member of a class?

struct S {
     static int f() { /*...*/ };

};

int main()
{
     int (S::*s)() = &S::f; // why?
}

Answer 1

Why a pointer cannot point to a static member of a class?

Because for the purpose of membership it isn't a member, merely for the purpose of scope. Apart from scope, static members are just like free functions, unattached to an instance of a class. You can use non-member function pointers:

int (*s)() = &S::f;

Answer 2

Whenever you do T::* , you're saying "this thing requires an instance of T to use." That statement does not hold for static functions, which are callable without any instances of the class.

Answer 3

You'd have to use a regular function pointer, like so:

int (*s)()=&S::f;

Like GMan said, static methods don't work on instances, so they don't receive the hidden this pointer. This effectively makes them have a different signature from instance methods with the same arguments.