junioriOS
What is Grand Central Dispatch (GCD)?
Updated May 6, 2026
Short answer
GCD manages concurrency and background tasks.
Deep explanation
Uses queues (main, global) to execute tasks asynchronously or synchronously.
Real-world example
Fetching API data without blocking UI.
Common mistakes
- Updating UI from background thread.
Follow-up questions
- What is main queue?
- Difference between sync and async?