为什么vptr不是静态的？ [英] Why vptr is not static?

问题描述

每个包含一个或多个虚函数的类都有一个与它相关的V表。一个名为vptr的void指针指向该vtable。该类的每个对象都包含指向同一个Vtable的vptr。那么为什么vptr不是静态的呢？而不是将vptr与对象关联，为什么不将它与类关联？

Every class which contains one or more virtual function has a Vtable associated with it. A void pointer called vptr points to that vtable. Every object of that class contains that vptr which points to the same Vtable. Then why isn't vptr static ? Instead of associating the vptr with the object, why not associate it with the class ?

推荐答案

对象的运行时类是对象本身的属性。实际上， vptr 表示运行时类，因此不能是 static 。但是，它指向的是同一个运行时类的所有实例可以共享的。

The runtime class of the object is a property of the object itself. In effect, vptr represents the runtime class, and therefore can't be static. What it points to, however, can be shared by all instances of the same runtime class.

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