to some random chunk o' memory with untyped/ unknown contents • ⼀一個任意指標,可⽤用來指向任何型別或內容的 記憶體區塊 • id • a reference to some random Objective-C object of unknown class • ⼀一個任意指標,可以指向 Obj-C 中的物件 http://justlink-linus.blogspot.tw/2012/11/id-void-void-pointer.html http://stackoverflow.com/questions/1304176/objective-c-difference-between-id-and-void