Wilson札記

最近剛開始學Objective-C剛好碰到Memory Management的問題，網路上有許多教學，我稍微將他們用圖匯整一下:

Objective-C Memory Management:

[retain]

   retatin count = 1            retatin count = 2        

                   after b = [ a retain ];

       a → □             →  　    a → □

                                                      ↑

                                                      b

[release]

   retatin count = 2     retatin count = 1      retatin count = 0

                  after  [ a release ];    after  [ a release ];

       a → □      →        □      →    □     auto execute dealloc

                 ↑                        ↑

                 b                        b

[copy]
   a retatin count = 1       a retatin count = 1    b retatin count = 1

                            after b = [ a copy ];

       a → □      →           a → □            b → □

[autorelease]

a = [[className alloc] init autorelease];

在autorelease pool中做個標記，若pool要release時，則會把每個已標記的對象release一次，如果某對象retain count > 1，則該對象還是沒有被銷毀。