swift - 从 swift 设置 char[] 到 c 结构中

Question

C 结构体中的 char[10] 作为 10 个 UInt8 项的元组导入。有很多关于如何从该结构成员中以 swift 字符串形式读取值的示例，但我希望能够在成员中设置某些内容？

struct CStrut {
char[10] item;
}

如何快速设置 item 的值？

Answer 1

一种方法是使用withUnsafeMutablePointer(_:_:):

var a = CStruct(item: (0, 1, 2, 3, 4, 5, 6, 7, 8, 9))
var CStructPtr = withUnsafeMutablePointer(&a.item) { (b) -> UnsafeMutableBufferPointer<Int8> in
    // UnsafeMutableBufferPointer is used because it a little more safe.
    return UnsafeMutableBufferPointer(start: UnsafeMutablePointer<Int8>(b), count: 10)
}

//Modify the tuple however you want
CStructPtr[0] = 42
CStructPtr[1] = 30