何时以及何时不使用Objective-C中的指针 [英] When to and when not to use pointers in Objective-C

问题描述

我知道关于指针的问题很多，尤其是对于Objective-C.但是我正在寻找更高层次的答案，以帮助我理解Objective-C中的范例.

我听说有人说在Objective-C中使用指针是一个问题或经验，即某些类要求使用指针，而另一些则不需要.这是真的?就是在Objective-C中使用指针的程度.

基本上，除了要显式地将引用变量传递给方法之外，Objective-C中指针的规则是什么?

解决方案

在引用堆中的内容时，总是使用指针 ；有时，当引用时，通常不使用指的是堆栈上的东西.

由于Objective-C对象总是分配在堆上(Blocks除外，但这与本讨论正交)，因此，您始终使用指向Objective-C对象的指针. id和Class类型实际上都是指针.

对于某些原始类型和简单结构，您不使用指针的地方. NSPoint，NSRange，int，NSUInteger等…通常通过堆栈访问 ，并且通常您不使用指针. /p>

对于Why the * in Objective-C?，您可能会发现以下问题感兴趣.

I know there are a lot of questions on pointers out there, particularly now for Objective-C. But I'm looking for some higher level answers to help me understand the paradigms in Objective-C.

I've heard some people say that using pointers in Objective-C is a matter or experience, i.e. some classes demand that you use pointers, others don't. Is this true? And is that the extent of using pointers in Objective-C.

Basically, apart from when you want to explicitly pass reference variable to methods, what are the rules for pointers in Objective-C?

解决方案

You use a pointer always when referring to something on the heap and sometimes, but usually not when referring to something on the stack.

Since Objective-C objects are always allocated on the heap (with the exception of Blocks, but that is orthogonal to this discussion), you always use pointers to Objective-C objects. Both the id and Class types are really pointers.

Where you don't use pointers are for certain primitive types and simple structures. NSPoint, NSRange, int, NSUInteger, etc... are all typically accessed via the stack and typically you do not use pointers.

As for Why the * in Objective-C?, you might find this question of interest.

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