对非常量对象的 const 引用

下面，在将 const 引用用于非 const 对象之前，是否会创建一个临时对象？

const int y = 2000;
const int &s = y // ok, const reference to const object.

int x = 1000;
const int &r = x; // any temporary copy here?

如果没有，那么这是如何运作的？

   const int z = 3000;
   int &t = z // ok, why can't you do this?

No.

A reference is simply an alias for an existing object. const is enforced by the compiler; it simply checks that you don't attempt to modify the object through the reference r.^* This doesn't require a copy to be created.

鉴于const只是向编译器发出强制执行“只读”的指令，那么您的最终示例无法编译的原因应该立即显而易见。const如果你可以通过采取非const参考一个const object.

_{* Of course, you are still free to modify the object via x. Any changes will also be visible via r, because they refer to the same object.}