NSAutoreleasePool自动释放池如何工作? [英] How does the NSAutoreleasePool autorelease pool work?

问题描述

据我了解，使用分配，新或副本创建的所有内容都需要手动发布.例如:

As I understand it, anything created with an alloc, new, or copy needs to be manually released. For example:

int main(void) {
    NSString *string;
    string = [[NSString alloc] init];
    /* use the string */
    [string release];
}

不过，我的问题是不是一样有效?:

My question, though, is wouldn't this be just as valid?:

int main(void) {
    NSAutoreleasePool *pool;
    pool = [[NSAutoreleasePool alloc] init];
    NSString *string;
    string = [[[NSString alloc] init] autorelease];
    /* use the string */
    [pool drain];
}

推荐答案

是的，您的第二个代码段是完全有效的.

Yes, your second code snippit is perfectly valid.

每次-autorelease发送到一个对象时，它就会被添加到最里面的autorelease池中.当池耗尽时，它只是向池中的所有对象发送-release.

Every time -autorelease is sent to an object, it is added to the inner-most autorelease pool. When the pool is drained, it simply sends -release to all the objects in the pool.

自动释放池只是一种便利，它使您可以将发送-release推迟到以后".这种后期"可能会在多个地方发生，但是在Cocoa GUI应用程序中最常见的是在当前运行循环周期结束时.

Autorelease pools are simply a convenience that allows you to defer sending -release until "later". That "later" can happen in several places, but the most common in Cocoa GUI apps is at the end of the current run loop cycle.

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