In Xcode, you can view all the header files of the cocoa-touch framework, but I'm just curious to see what some of the implementations look like. Is there a way to see them? They must be on the system somewhere, right? The header doesn't do anything without the implementation.
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They are your contract or entry-point into those binaries.
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The iPhone SDK is currently closed-sourse so you won't be able to get access to the implementation files, sorry..
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It might give you some idea of how things work..