How to use C++11 std::is_member_object_pointer in type_traits?

Question

struct A { int x; };

int main() {
    int A::* pt = &A::x;
    return 0;
}

what does int A::* mean exactly? I have never seen C++ syntax like this.

See here: https://stackoverflow.com/questions/670734/c-pointer-to-class-data-member — Vertexwahn, May 27 '17 at 09:45
Possible duplicate of [C++: Pointer to class data member](https://stackoverflow.com/questions/670734/c-pointer-to-class-data-member) — Sam Twidale, May 27 '17 at 16:49

score 2 · Accepted Answer · answered May 27 '17 at 10:59

Just like other traits, you specify the template argument and use the value member.

std::is_member_object_pointer<decltype(pa) >::value

what does int A::* mean exactly?

That is a type declaration of a member object pointer to an int member of the class A.

1 Answers1