Kas on ühine run loop kõigi järjekordade jaoks või iga järjekord omab oma run loopi?

Run loop is associated with a thread, not with a queue. Each main thread has its own run loop, which is created automatically. Background threads typically do not have one by default, but can be created and started if needed. GCD queues do not have their own run loops; they manage task execution based on a thread pool (sometimes using the main thread).

// Get the current run loop for the current thread
let currentRunLoop = RunLoop.current

// Check if the current thread is the main thread
if Thread.isMainThread {
    print("Current thread is the main")
    // The main thread always has a run loop
} else {
    print("Background thread")
    // Background thread may need to create and start a run loop explicitly
}

// GCD queues do not have a run loop property
// DispatchQueue.global().sync {
//     Just execute the task
// }

• Main Thread: Has a RunLoop that is created automatically. It handles UI events, timers, and other asynchronous operations.
• Background threads: May have a RunLoop if needed (e.g., for managing timers or ports), but they need to be initialized and started manually.
• GCD queues: Do not directly use RunLoop. They enqueue tasks, which are then executed on available threads from the pool.