auto release pool 应该用release还是drain

最新推荐文章于 2018-08-08 17:53:40 发布

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最新推荐文章于 2018-08-08 17:53:40 发布

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原文链接：https://my.oschina.net/amoyai/blog/103502

本文探讨了在iOS开发环境中drain与release方法的作用及其差异。在引用计数环境中，drain方法的行为与release相同，导致接收者被释放；在垃圾回收环境中，drain最终调用objc_collect_if_needed。在iOS开发中，两者作用相同。

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文档里是这么说的：

drain

In a reference-counted environment, releases and pops the receiver; in a garbage-collected environment, triggers garbage collection if the memory allocated since the last collection is greater than the current threshold.

- (void)drain

Discussion

In a reference-counted environment, this method behaves the same as release. Since an autorelease pool cannot be retained (see retain), this therefore causes the receiver to be deallocated. When an autorelease pool is deallocated, it sends a release message to all its autoreleased objects. If an object is added several times to the same pool, when the pool is deallocated it receives a release message for each time it was added.

In a garbage-collected environment, this method ultimately calls objc_collect_if_needed.

Special Considerations

In a garbage-collected environment, release is a no-op, so unless you do not want to give the collector a hint it is important to use drain in any code that may be compiled for a garbage-collected environment.

对于iOS来说drain和release的作用其实是一样的。

转载于:https://my.oschina.net/amoyai/blog/103502