如何将UnsafePointer <cunsignedchar>转换为String？</cunsignedchar>

Question

我尝试过这种方法：

String.stringWithCString(cString: UnsafePointer<CChar>, encoding: NSStringEncoding)

但不幸的是，它只适用于UnsafePointer<CChar>。我不知道如何将UnsafePointer<CUnsignedChar>转换为UnsafePointer<CChar>。

Answer 1

struct UnsafePointer<T>有一个构造函数，它接受一个不同的不安全指针 输入参数：

/// Convert from a UnsafePointer of a different type.
///
/// This is a fundamentally unsafe conversion.
init<U>(_ from: UnsafePointer<U>)

因此您可以从ptr : UnsafePointer<CUnsignedChar>创建字符串 与

let str = String.stringWithCString(UnsafePointer(ptr), encoding: someEncoding)

或者，在UTF-8编码的情况下，更简单地使用

let str = String.fromCString(UnsafePointer(ptr))

请注意，泛型类型<CChar>会自动从此处的上下文中推断出来， 即最后一行相当于

let str = String.fromCString(UnsafePointer<CChar>(ptr))

Answer 2

从 Swift 3.0 开始

let str = String(cString: UnsafePointer<CChar>(ptr))