C Union equivalent in Swift

In C we can declare unions as follows:

union Data {
   int i;
   uint u;
} data;

union Data {

int i;

uint u;

} data;

So the same storage is used for the int and uint.

We can achieve something similar in Swift using bitPattern.

let a: Int8 = 1
let b = UInt8(bitPattern: a)

let negativeA: Int8 = -1
let bFromNegative = UInt8(bitPattern: negativeA)

let a: Int8 = 1

let b = UInt8(bitPattern: a)

let negativeA: Int8 = -1

let bFromNegative = UInt8(bitPattern: negativeA)

In the above example b is 1 and bFromNegative is 255 (the two complement of -1).

UInt8(bitPattern: … initialiser will use the same bit storage.