withUnsafeBytes(_:)

Declaration

func withUnsafeBytes<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R

Parameters

• body:

  A closure with an Unsaferawbufferpointer parameter that points to the contiguous storage for the type. If no such storage exists, the method creates it. If body has a return value, this method also returns that value. The argument is valid only for the duration of the closure’s execution.

Return Value

The return value, if any, of the body closure parameter.

Discussion

The following example copies the bytes from a string encoded using utf8 into a buffer of UInt8:

let data = "Hello".data(using: .utf8)
var byteBuffer: [UInt8] = []
_ = data?.withUnsafeBytes { buffer in
    byteBuffer.append(contentsOf: buffer)
}

// byteBuffer = [72, 101, 108, 108, 111]