What are the alternative approaches to multithreading management besides using GCD?

In addition to Grand Central Dispatch (GCD), there are other approaches to managing multithreading in iOS:

• NSThread — a lower-level API for creating and managing threads manually. It allows creating separate threads but requires more control and responsibility.

• Operation and OperationQueue — an object-oriented approach built on top of GCD. It allows creating operations (Operation), which can be queued (OperationQueue), setting dependencies between operations, canceling them, and managing priorities.

• POSIX Threads (pthread) — a low-level C API for working with threads, rarely used in iOS but available.

• Swift Concurrency (async/await) — a modern approach introduced in Swift 5.5, which simplifies asynchronous programming by allowing writing asynchronous code in a synchronous style.

Example of using OperationQueue:

let queue = OperationQueue()
queue.addOperation {
    print("Executing task in background")
}

Thus, the choice of approach depends on requirements for control, convenience, and compatibility with existing code.