This document discusses blocks and Grand Central Dispatch (GCD) in Objective-C. It introduces blocks as closures that can be passed around like objects, explains their advantages over function pointers, and demonstrates their use. It also outlines the key components of GCD including main dispatch queues, concurrent queues, serial queues, groups to synchronize work, and sources to integrate events. Sample code is provided to demonstrate blocks and GCD.

1. Blocks
Grand Central Dispatch

2. Blocks / GCD
• Objective-C 2.1
• Snow Leopard
• iOS 4

3. Blocks
• lambda, closure
• Lisp, SmallTalk, Ruby
• C, C++, Objective-C

4. ^

5. DEMO

6. Block
• Blocks Objective-C
• Block
• copy
• release Block

7. Block
• Blocks
retain
• Block
__block

8. Blocks vs Function Pointer
• vs
•
•

9. Grand Central Dispatch
•
•
•
• Blocks

10. GCD

11. GCD

12. GCD

13. GCD Queue
• Main dispatch queue
• Concurrent queue
• Serial queue

14. Main dispatch Queue

15. Concurrent Queue

16. Serial Queue

17. GCD Group
• dispatch_group_create
• dispatch_group_async
• dispatch_group_wait
• Thread join

18. GCD Sources
•
•
• Event handler GCD Queue

19. GCD Source

20. DEMO

21. •
• Introducing Blocks and Grand Central Dispatch
• Concurrency Programming Guide
• Grand Central Dispatch (GCD) Reference
• WWDC 2010: Session 206, 211