Interview guides / ios

GCD vs Swift Concurrency: iOS Interview Question

GCD vs Swift Concurrency interview question with a clear example answer for iOS engineers. Practice with AceMobileInterview.

This is a common iOS interview topic: GCD vs Swift Concurrency.

Below is a concise answer you can adapt in a real interview, then go deeper in the full AceMobileInterview track.

1. 1.Compare GCD (DispatchQueue) with async/await and actors. When would you still reach for GCD?

   GCD is queue-based concurrency; Swift Concurrency models tasks, structured cancellation, and actor isolation for data races. Prefer async/await for new code, MainActor for UI, and actors for shared mutable state. GCD still helps for fine-grained QoS tuning, integrating C APIs, or migrating legacy code incrementally.