void *和id有什么区别？(What's the difference between void* and id? [duplicate])

void *和id有什么区别？(What's the difference between void* and id? [duplicate])

可能重复： id和void之间的客观c差异*

例如，UIView动画委托回调方法有这个参数：

context:(void*)context

为什么不简单地ID？ 如果我不关心上下文，我总是通过零。 但是当我想要一个时，我传递了这个对象。 有什么不同？ 为什么他们更喜欢void * over id？

Possible Duplicate: objective c difference between id and void *

For example, an UIView animation delegate callback method has this argument:

context:(void*)context

Why not simply id? I always pass nil if I don't care about an context. But when I want one, I pass the object. What's the difference? Why did they prefer void* over id?

最满意答案

id是一个指向具有isa指针的结构的指针（它指向ObjectiveC运行时，这个“thing”是对象）。 void*只是指向可能的任何东西（可能是另一个id ）的指针。

id is a pointer to a struct which has isa pointer (which denotes to ObjectiveC runtime that this "thing" is object). void* is simply a pointer to possibly anything (probably another id).