我發現以下代碼可以編譯并運行：func foo(p:UnsafePointer<UInt8>) {    var p = p    for p; p.memory != 0; p++ {        print(String(format:"%2X", p.memory))    }}let str:String = "今日"foo(str)這將打印出來E4BB8AE697A5，并且是UTF8的有效表示形式今日據我所知，這是未記錄的行為。從文檔中：當一個函數被聲明為帶有UnsafePointer參數時，它可以接受以下任何一個：nil，作為空指針傳遞UnsafePointer，UnsafeMutablePointer或AutoreleasingUnsafeMutablePointer值，必要時將其轉換為UnsafePointer一個In-out表達式，其操作數是Type類型的左值，作為左值的地址傳遞一個[Type]值，作為指向數組開頭的指針傳遞，并在調用期間進行生命周期擴展在這種情況下，str不是他們。我想念什么嗎？添加：如果參數類型是 UnsafePointer<UInt16>func foo(p:UnsafePointer<UInt16>) {    var p = p    for p; p.memory != 0; p++ {        print(String(format:"%4X", p.memory))    }}let str:String = "今日"foo(str)//  ^ 'String' is not convertible to 'UnsafePointer<UInt16>'即使內部String表示形式為UTF16let str = "今日"var p = UnsafePointer<UInt16>(str._core._baseAddress)for p; p.memory != 0; p++ {    print(String(format:"%4X", p.memory)) // prints 4ECA65E5 which is UTF16 今日}