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(Xcode 10.1, Apple Swift version 4.2.1 (swiftlang-1000.11.42 clang-1000.11.45.1))I'm developing an App (my first one) and during the development process I'd rather have a debug window into which I can write messages for development and debugging purposes.I have a UItextView for this and to get all print() into that textView, I'm using the following construct (pipe()) inspired by this:// // ViewController.swift // Scroll View Demo // // Created by chriskuku on 30.12.18. // Copyright © 2018 chriskuku. All rights reserved. // import UIKit class ViewController: UIViewController { @IBOutlet weak var textView: UITextView! @IBOutlet weak var writeButton: UIButton! var pipe = Pipe() var count = 0 override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically from a nib. // dup2() makes newfd (new file descriptor) be the copy of oldfd (old file descriptor), closing newfd first if necessary. dup2(pipe.fileHandleForWriting.fileDescriptor, STDOUT_FILENO) // listening on the readabilityHandler pipe.fileHandleForReading.readabilityHandler = { [weak self] handle in let data = handle.availableData let str = String(data: data, encoding: .ascii) ?? "\n" DispatchQueue.main.async { self?.textView.text += str } } print("\npipe started") } @IBAction func buttonPressed(_ sender: Any) { print("\(count). Hello world") count += 1 } }The App works fine when being run within Xcode on either virtual device (iPhone 6s plus in my case) or physially on the device connected to Xcode.But when I run the app alone on the target device (Apple iPhone 6splus), the pipe() mechanism doesn't seem to work. Nothing appears but the Initial text.I'm puzzled.