T::* 在模板参数中是什么意思？

Question

继 here 中写的文章之后：

我遇到了这段代码（为清楚起见，进行了缩短和更改）：

template <class T> struct hasSerialize
{
    // This helper struct permits us to check that serialize is truly a method.
    // The second argument must be of the type of the first.
    // For instance reallyHas<int, 10> would be substituted by reallyHas<int, int 10> and works!
    // reallyHas<int, &C::serialize> would be substituted by reallyHas<int, int &C::serialize> and fail!
    // Note: It only works with integral constants and pointers (so function pointers work).
    // In our case we check that &C::serialize has the same signature as the first argument!
    // reallyHas<std::string (C::*)(), &C::serialize> should be substituted by 
    // reallyHas<std::string (C::*)(), std::string (C::*)() &C::serialize> and work!
    template <typename U, U u> struct reallyHas;

    // We accept a pointer to our helper struct, in order to avoid to instantiate a real instance of this type.
    // std::string (C::*)() is function pointer declaration.
    template <typename C>
    static char&
    test(reallyHas<std::string (C::*)(), &C::serialize>* /*unused*/) { }
};

所以这个

std::string (C::*)()

引起了我的注意。

任何人都可以向我解释 C::* 部分吗？那是一个函数指针 returns std::string 但还有什么？

Answer 1

指向class C 中成员的成员函数指针 returns a std::string.

检查 isocpp.org 以获取有关指向成员函数的指针的更多信息。