Objective-C Blocks and GCD

Introduction

Blocks are Objective-C's closure implementation, providing anonymous functions that capture surrounding context. Grand Central Dispatch (GCD) is Apple's low-level API for managing concurrent operations using dispatch queues rather than threads directly.

Blocks enable functional programming patterns, callbacks, and clean asynchronous API design. GCD simplifies concurrency by abstracting thread management into queues that automatically distribute work across available CPU cores. Together, they form the foundation for modern Objective-C concurrent programming.

This skill covers block syntax and semantics, capture behavior, GCD queues and dispatch functions, synchronization primitives, and patterns for safe concurrent code.

Block Syntax and Usage