目标 C 中 self.variable 和变量赋值的区别 [英] Objective C difference between self.variable and variable assignments

问题描述

我怕我很笨.

我花了大约三个小时来追踪破坏我理智的内存泄漏，在注释掉我的一半应用后，我得出了以下结论.

I've spent about three hours tracking down a memory leak that's been destroying my sanity and after commenting out half my app I have come to the following conclusion.

在正确的位置给出以下内容.

Given the following in the right places.

NSString *blah;

@property (nonatomic, retain) NSString *blah;

@synthesize blah;

-(id)initWithBlah:(NSString*)b {

     self.blah = b;    //this leaks
     blah = b;         //this does not

}

我对objectice c 不是特别有经验，我知道如果我在课堂之外调用object.blah = b;我会透明地调用一个 setter 函数，该函数将保留 b.在我通过设置 self.blah = b 假设的函数内部，我出于某种原因双重保留?

I am not particularly experienced with objectice c, I understand that outside of the class if I were calling object.blah = b; I would be transparently calling a setter function which would retain the b. Inside the function I'm presuming by setting it with self.blah = b I'm double retaining for some reason?

有人可以向我解释为什么会这样，或者如果不是的话，我可能做错了什么?

Could someone explain to me why that's the case or if not what I might be doing wrong?

干杯

推荐答案

你错了.blah = b; 赋值意义不大，因为在您的代码从 initWithBlah: 返回后，您不能再依赖周围的字符串.每当您下次访问它时，它很可能已经被释放.

You are mistaken. The blah = b; assignment makes little sense because after your code returns from initWithBlah: you can no longer rely on the string being around. Whenever you access it next, it has very probably already been deallocated.

self.blah = b; 赋值是正确的，因为它调用了 setter，因此你获得了字符串的所有权.当然，您也必须在 -dealloc 中释放 blah 以防止内存泄漏.

The self.blah = b; assignment is correct because it calls the setter and thereby you take ownership of the string. Of course, you have to release blah in your -dealloc, too, to prevent memory leaks.

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