Concurrency in Swift (iOS/macOS)

The book "Concurrency in Swift (iOS/macOS)" is a practical guide to creating fast, responsive, and reliable applications for Apple platforms. It covers all major topics related to parallel code execution: from the classic Grand Central Dispatch (GCD) mechanisms to the modern async/await model introduced in Swift 5.5.

The author systematically breaks down key concepts that will help you avoid data races, deadlocks, and thread leaks. You will learn how to properly organize multithreaded computations, work with queues, semaphores, and locks. Special attention is given to safe access to shared data through Actors and sending signals between tasks.

Who this book is for:

• iOS/macOS developers with 1+ years of experience who want to deepen their knowledge of multithreading;
• programmers transitioning from Objective-C to Swift who want to master modern approaches;
• developers facing performance issues and UI freezes;
• professionals preparing for technical interviews for the Senior iOS Developer position.

What you will learn:

• How threads, queues, and dispatching work in iOS/macOS;
• Practical techniques for using GCD: dispatch queues, groups, semaphores, barriers;
• A complete guide to async/await: creating and canceling Task, TaskGroup, structured concurrency;
• How to use Actors for state isolation and preventing data races;
• UI optimization through asynchronous interface updates and main thread operations;
• Testing concurrent code and debugging multithreading errors;
• Real-world cases: image loading, network operations, processing large data arrays.

Each chapter contains code examples that can be immediately applied in a project. The book is written in an engaging style and is suitable both for self-study and as a reference for daily work. After reading it, you will be able to confidently design application architectures with high performance and responsiveness.

If you want to stop fearing multithreading and start using it to its full potential — this book is for you.