在ARC下，通过属性分配给ivar时，是否会自动复制块? [英] Under ARC, are Blocks automatically copied when assigned to an ivar via the property?

问题描述

假设

typedef void (^MyResponseHandler) (NSError *error);
@property (strong, nonatomic) MyResponseHandler ivarResponseHandler;
synthesize ivarResponseHandler = _ivarResponseHandler;

- (void)myMethod:(MyResponseHandler)responseHandler
{
    self.ivarResponseHandler = responseHandler;
    ...
}

通过@property分配给ivar是否正确?我知道在手动内存管理中，您需要self.ivarResponseHandler = [responseHandler copy];来确保将块从堆栈复制到堆.但是，在观看WWDC 2011的第322节-深度上的Objective-C进步(第25分钟)时，这位演讲者说ARC自动处理了将块分配给ivar的问题.我只是想确定一下.

Is the assignment to the ivar through the @property correct? I know that in manual memory management you would have needed self.ivarResponseHandler = [responseHandler copy]; to make sure the block was copied from the stack to the heap. But watching Session 322 - Objective-C Advancements in Depth (minute 25) from WWDC 2011, the speaker says that ARC automatically handles the assignment of a block to an ivar. I just wanted to make sure.

推荐答案

bearMountain，

bearMountain,

实际上，确保复制块的最简单方法是将@property设置为使用复制.如:

The easiest way to ensure the block is copied is to, in fact, set the @property to use copy. As in:

@property (copy, nonatomic) MyResponseHandler ivarResponseHandler;

它可以满足您的所有需求.

It does everything you need.

安德鲁

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