取参考成员的偏移量(非POD) [英] Taking offset of a reference member (non PODs)

问题描述

这是代码段

#include <iostream>
struct Z
{
   Z():x(0),y(0),z(x){}
   ~Z(){}

   int x;
   int y;
   int &z; // Reference member
};
template <typename Type, typename C, typename M>
size_t Offsetof (M C::* ptr_to_member)
{
  Type type;
  return reinterpret_cast<char*> (&(type.*ptr_to_member)) - reinterpret_cast<char*> (&type);
}
int main()
{
   std::cout << Offsetof<Z>(&Z::x); // works
   std::cout << Offsetof<Z>(&Z::y); // works 
   std::cout << Offsetof<Z>(&Z::z); // doesn't work
}

我们无法创建引用指针，因此功能Offsetof不适用于z.

We cannot create pointer to reference so the function Offsetof won't work for z.

对于非POD，有什么方法可以使参考数据成员偏移吗?

Is there any way to take offset of a reference data member for non PODs?

推荐答案

否.引用不是对象，它们不存在或没有地址或偏移量.指向成员引用的指针是非法的.

No. References are not objects, and they do not exist or have addresses or offsets. A pointer to a member reference is illegal.

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