Everything in C is exactly the same in Objective-C.The framework can do a lot for you, but only if your app is properly factored into Model, View, and Controller. Failure to do so will make development harder, because you will be doing more work. Maintain the MVC separation at all times. Cocoa and Cocoa Touch are designed around Model-View-Controller.Read both of those documents from start to finish. The definitive word on this subject is in the Memory Management Programming Guide for Cocoa and the Memory Management Programming Guide for Core Foundation. If object A does not own object B, but does (a), (b), or (c), then object B is over-retained, and, assuming that object A does not release it, object B will become a leak. When object A goes to use it, you will crash. If object A owns object B, but has not done (a), (b), or (c), then object B is under-retained and may die while object A is holding on to it. If object A does not own object B, then in cases (a) and (b), it should have autoreleased object B immediately after creating it, and case (c) usually should not happen at all. Instead, think about ownerships.ĭoes object A own object B? If so, then it should have either (a) created object B itself, (b) copied object B from some other object, or (c) retained object B upon receiving it from elsewhere.

They are practically useless and frequently misleading. Ignore the retainCount method and its Core Foundation equivalent. Make a copy of the object, and own that.Take co-ownership of the object by retaining it.If you don't own an object, but you want to, then you have two choices: If you own an object, you are obliged to release it.If you make a copy of an existing object using a method whose selector contains the word “copy”, or from a function whose name contains the word “Copy” (or obtain an object from such a function), then you own the copy.If you create an object with a method whose selector contains the word “alloc” or “new”, or with a function whose name contains the word “Create”, then you own it.If you're using or supporting GC, see the Garbage Collection Programming Guide.) (These rules don't apply under garbage collection.

Memory management is based on ownership.

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