如何在C ++类模板中访问指向成员参数的指针？

Question

I'm trying to create a C++ class template that takes advantage of a pointer to member parameter but compilation fails. How do I access the pointer to member parameter from within the template?

class Base {
public:
  int foo;
  int bar;
};

template<int Base::* T>
class Derived : public Base {
public:
  int Get() { return *T; }  <--- Does not work
};

Derived<&Base::foo> test;
printf("Value = %i\n", test.Get());

The compilation error from Clang is indirection requires pointer operand ('int Test::*' invalid) .

Answer 1

Try

int Get() { return this->*T; }

.* and ->* are the operators for dereferencing pointers-to-members.

Answer 2

return this->*T;

（为什么T ？这不是一种类型。）