Objective C [对象释放]
我正在查看其他人的代码，但它似乎释放了对象 VIDEO，但随后继续使用它。
现在，根据我对面向对象编程语言的理解，一旦它被释放，它应该从内存中释放......
我看不出它如何有任何引用......但我假设这就是它没问题的原因。似乎是一件奇怪的事情，（当你还没有完成它时释放它，为什么不使用 autorelease 例如）。
self.video = [[VideoFrameExtractor alloc] initWithVideo:[Utilities bundlePath:@"sophie.mov"]];
[video release];
// set output image size
video.outputWidth = 426;
video.outputHeight = 320;
I'm looking at someone else's code, but it appears to RELEASE object VIDEO but then continue to use it.
Now from my understanding of Object Oriented Programming languages, once it's released, it should be dealloc'd from memory...
I can't see how it has any references...but I'm assuming that's the reason it's OK. Seems like a strange thing to do, (Release it when you haven't finished with it, why not use autorelease for example).
self.video = [[VideoFrameExtractor alloc] initWithVideo:[Utilities bundlePath:@"sophie.mov"]];
[video release];
// set output image size
video.outputWidth = 426;
video.outputHeight = 320;
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它相当于：
self.video = [[[VideoFrameExtractor alloc] initWithVideo:[Utilities bundlePath:@"sophie.mov"]] autorelease];（假设视频由 self 保留）
通过避免尽可能使用自动释放池，并且它有助于定位代码中有关引用计数的错误。 soo...假设属性是保留或复制，那么 self 应该恰好保存一个引用 - 这是完美的。
希望有帮助。
it's equivalent to:
self.video = [[[VideoFrameExtractor alloc] initWithVideo:[Utilities bundlePath:@"sophie.mov"]] autorelease];(assuming the video is retained by self)
there's a small performance boost by avoiding autorelease pools where possible, as well as it helps localize errors in your code regarding ref counting. soo... assuming the property is retain or copy, then self should hold exactly one reference - which is perfect.
hope that helps.
此行实际上调用
-setVideo:方法，其中视频变量可能被保留（如果使用保留属性声明了相应的属性）。因此视频对象的保留计数变为 2，为了补偿额外的保留，我们释放它。仅当对象的保留计数变为 0 时，对象才会被释放，因此这样做是安全的。我们还需要在代码中的某个位置（例如在 dealloc 方法中）释放视频，以确保视频对象在不需要时被销毁，以避免内存泄漏
this line actually calls
-setVideo:method where video variable is likely being retained (if corresponding property is declared with retain attribute). So retain count of video object becomes 2 and to compensate extra retain we release it. Object gets dealloced only when its retain count becomes 0, so it is safe to do so.We also need to release video somewhere in the code (e.g. in dealloc method) to be sure video object gets destroyed when it is not needed to avoid memory leak