<E版原文>

　Objective-C supports two mechanisms for memory management: automatic garbage collection and reference counting:

• Garbage Collection Programming Guidedescribes the garbage collection system used in Mac OS X. (Not available for iOS—you cannot access this document through the iOS Dev Center.)

• Memory Management Programming Guidedescribes the reference counting system used in iOS and Mac OS X.

<译文>

 Object-C 支持两种机制的内存管理：自动垃圾收集机制 和 引用计数机制。

1.垃圾收集机制在iOS下不可用。

2.《Memory Managerment Programming Guide》描述了在iOS和Mac OS X中的引用计数系统。