9 Declarations [dcl.dcl]

9.3 Declarators [dcl.decl]

9.3.4 Meaning of declarators [dcl.meaning] Pointers to members [dcl.mptr]

The component names of a ptr-operator are those of its nested-name-specifier, if any.
In a declaration T D where D has the form and the nested-name-specifier denotes a class, and the type of the contained declarator-id in the declaration T D1 is “derived-declarator-type-list T”, the type of the declarator-id in D is “derived-declarator-type-list cv-qualifier-seq pointer to member of class nested-name-specifier of type T.
The optional attribute-specifier-seq ([dcl.attr.grammar]) appertains to the pointer-to-member.
[Example 1: 
struct X { void f(int); int a; }; struct Y; int X::* pmi = &X::a; void (X::* pmf)(int) = &X::f; double X::* pmd; char Y::* pmc; declares pmi, pmf, pmd and pmc to be a pointer to a member of X of type int, a pointer to a member of X of type void(int), a pointer to a member of X of type double and a pointer to a member of Y of type char respectively.
The declaration of pmd is well-formed even though X has no members of type double.
Similarly, the declaration of pmc is well-formed even though Y is an incomplete type.
pmi and pmf can be used like this: X obj; // ... obj.*pmi = 7; // assign 7 to an integer member of obj (obj.*pmf)(7); // call a function member of obj with the argument 7
— end example]
A pointer to member shall not point to a static member of a class ([class.static]), a member with reference type, or “cv void.
[Note 1: 
The type “pointer to member” is distinct from the type “pointer”, that is, a pointer to member is declared only by the pointer-to-member declarator syntax, and never by the pointer declarator syntax.
There is no “reference-to-member” type in C++.
— end note]