在dealloc中将IBOutlets设置为nil [英] Settings IBOutlets to nil in dealloc

问题描述

在此处的内存警告部分 http://developer.apple.com/iphone/library/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmNibObjects.html ，我不明白IBOutlet在dealloc中设置为nil的原因。如果

In the section titled 'Memory Warnings' here http://developer.apple.com/iphone/library/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmNibObjects.html, I don't follow why the IBOutlet is set to nil in the dealloc. If

self.anOutlet = nil

导致主题中提到的崩溃，为什么他们将ivar设置为nil？

causes a crash as mentioned in the topic, why are they setting the ivar to nil?

一般来说， $

In general, why would you set an ivar to nil in the dealloc when you are already calling release?

推荐答案

c $ c>，指针本质上无效，并再次访问可能会导致崩溃。通过在 release 后设置一个变量 nil ，可以防止发生崩溃。

After a release, the pointer is essentially invalid and accessing it again may cause a crash. By setting a variable to nil after release you prevent that crash from happening. There's no harm in accessing a nil pointer.

您链接的示例简单地说明了为什么将变量或ivar设置为 nil 之后 release ，即使看起来像变量/ ivar将不会被再次访问。

The example you've linked to simply demonstrates why it's always a good idea to set a variable or ivar to nil after release, even when it looks like the variable/ivar won't be accessed again.

在示例中， anOutlet ivar实际上是由 dealloc 方法，所以如果你不设置为nil，你会得到一个崩溃。像这样的情况很难通过查看代码，所以这是一个好主意nil每个变量释放后，即使在dealloc。

In the example, the anOutlet ivar is actually accessed by the superclass after your dealloc method, so if you don't set it to nil you will get a crash. Scenarios like that are very hard to spot just by looking at the code, so it's a good idea to nil every variable after release, even in dealloc.

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