Objective-C类实例在alloc处归零？ [英] Objective-C class instance zeroed at alloc?

问题描述

当我第一次分配一个类实例时，是否有任何类型的内存清零目标-c代表我进行？我看到很多Objective-c代码默认情况下假设它们的出口是 nil 。如果我这样做，我会基于虚假借口进行此类行为吗？

Is there any kind of memory-zeroing objective-c undertakes on my behalf when I first allocate a class instance? I see a lot of objective-c code out there that presumes their outlets are nil by default. If I do the same am I basing such behavior on false pretenses?

推荐答案

NSAllocateObject 返回一个足够大的内存块，以包含类中的所有ivars;其 isa 指针设置为该类，其余部分填充为0. + [NSObject alloc] 调用 + [NSObject allocWithZone：] 然后在内部调用 NSAllocateObject 。

NSAllocateObject returns a block of memory large enough to include all the ivars in the class; its isa pointer is set to the class, and the rest of the block is filled with 0. +[NSObject alloc] calls +[NSObject allocWithZone:] which then calls NSAllocateObject internally.

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