iOS Development learning Note 013-ARC mechanism

ARC

1. ARC mechanism

2. ARC Judging Criteria

ARC mechanism

ARC is a compiler attribute, not an IOS runtime feature, nor is it similar to a garbage collector in other languages. So ARC and manual memory management performance is the same, and sometimes faster, because the compiler can also perform some optimizations

ARC Judging criteria:

The object is freed as long as there is no strong pointer.

The hands are divided into 2 types:

Strong pointers: The default is strong pointers (__strong)

__strong person *p; __strong can not write, the default is __strong

Weak pointers: Objects declared with (__weak)

__weak person *p;

Precautions

iOS Development learning Note 013-ARC mechanism