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General topic questions

GCD vs Swift Concurrency

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Free section · general topics & algorithms

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

Reveal model answer
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.
ARC and retain cyclesGenerics Basics