为什么我的自动释放对象没有被释放？
我正在调试一个奇怪的内存管理错误，但我无法弄清楚。我注意到我的一些对象在内存中停留的时间比预期的要长。我检查了所有内存管理，最后得出了一个非常不可能的结论：我的一些 autorelease 操作不会导致release。什么情况下可以呢？我创建了一个小型测试 Canary 类，该类在 dealloc 中记录一条消息，并具有以下测试代码：
NSLog(@"On the main thread: %i.", [NSThread isMainThread]);
[[[Canary alloc] init] autorelease];
根据代码，我们实际上位于主线程上，但是 Canary 中的 dealloc 直到很久以后才会被调用。延迟是不确定的，很容易需要几秒钟或更长时间。这怎么可能？应用程序在 Mac 上运行，垃圾收集已关闭（Objective-C 垃圾收集在目标上设置为不支持。）我主要习惯于 iOS，是OS X 上的内存管理在某些重要方面有所不同？
I am debugging a weird memory management error and I can’t figure it out. I noticed that some of my objects are staying in memory longer than expected. I checked all my memory management and finally got to the very improbable conclusion that some of my autorelease operations don’t result in a release. Under what circumstances is that possible? I created a small testing Canary class that logs a message in dealloc and have the following testing code in place:
NSLog(@"On the main thread: %i.", [NSThread isMainThread]);
[[[Canary alloc] init] autorelease];
According to the code we’re really on the main thread, but the dealloc in Canary does not get called until much later. The delay is not deterministic and can easily take seconds or more. How is that possible? The application runs on a Mac, the garbage collection is turned off (Objective-C Garbage Collection is set to Unsupported on the target.) I am mostly used to iOS, is memory management on OS X different in some important way?
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autorelease无法按预期运行的唯一情况是当前线程上没有自动释放池。只有少数情况会发生这种情况，如果确实发生，您会在控制台上打印一条非常响亮的日志消息。如果您没有看到该日志，则autorelease的行为正常。更有可能的是，您的代码中的某些内容正在调用此 Canary 对象的retain，然后永远不会释放它。The only circumstance in which
autoreleasedoes not behave as expected is when there is no autorelease pool on the current thread. There are only a few situations where you can expect this to occur, and if it does, you get a very loud log message printed to the console. If you're not seeing that log, thenautoreleaseis behaving appropriately. Far more likely is the fact that something on your code is callingretainon this Canary object and then never releasing it.自动释放的对象在其池耗尽之前不会被释放。因此，如果您使用自动释放缓冲区循环遍历图像，那么每次循环时最好创建并排出一个池。
Autoreleased objects do not get released until their pool is drained. So, if you are looping through images with an autoreleased buffer, it would be good to create and drain a pool every time through the loop.
Mike Ash 发表了一篇名为 Autorelease 的更多乐趣 的博文，其中介绍了解释了这个问题的根源。引用：
我发誓我必须从头到尾阅读该博客，这是一次很好的时间投资。
There’s a blog post by Mike Ash called More Fun With Autorelease that explains the source of this problem. Quote:
I swear I have to read the blog from cover to cover, it’s a good time investment.