# transcode(_:from:to:stoppingOnError:into:) Translates the given input from one Unicode encoding to another by calling the given closure. ``` func transcode(_ input: Input, from inputEncoding: InputEncoding.Type, to outputEncoding: OutputEncoding.Type, stoppingOnError stopOnError: Bool, into processCodeUnit: (OutputEncoding.CodeUnit) -> Void) -> Bool where Input : IteratorProtocol, InputEncoding : _UnicodeEncoding, OutputEncoding : _UnicodeEncoding, Input.Element == InputEncoding.CodeUnit ``` ## Parameters `input` An iterator of code units to be translated, encoded as `inputEncoding`. If `stopOnError` is `false`, the entire iterator will be exhausted. Otherwise, iteration will stop if an encoding error is detected. `inputEncoding` The Unicode encoding of `input`. `outputEncoding` The destination Unicode encoding. `stopOnError` Pass `true` to stop translation when an encoding error is detected in `input`. Otherwise, a Unicode replacement character (`"\u{FFFD}"`) is inserted for each detected error. `processCodeUnit` A closure that processes one `outputEncoding` code unit at a time. ## Return Value `true` if the translation detected encoding errors in `input`; otherwise, `false`. ## Discussion The following example transcodes the UTF-8 representation of the string `"Fermata 𝄐"` into UTF-32. ``` let fermata = "Fermata 𝄐" let bytes = fermata.utf8 print(Array(bytes)) // Prints "[70, 101, 114, 109, 97, 116, 97, 32, 240, 157, 132, 144]" var codeUnits: [UTF32.CodeUnit] = [] let sink = { codeUnits.append($0) } transcode(bytes.makeIterator(), from: UTF8.self, to: UTF32.self, stoppingOnError: false, into: sink) print(codeUnits) // Prints "[70, 101, 114, 109, 97, 116, 97, 32, 119056]" ``` The `sink` closure is called with each resulting UTF-32 code unit as the function iterates over its input. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)