What tools do you use to coordinate the execution of concurrent tasks in applications?

The following tools are commonly used for coordinating the execution of concurrent tasks in iOS applications:

• GCD (Grand Central Dispatch) — a low-level API for managing task queues, allowing code to be executed asynchronously or synchronously on different threads.

• OperationQueue and Operation — a higher-level mechanism based on GCD, with the ability to manage dependencies between tasks, priorities, and cancellation.

• DispatchGroup — for grouping multiple asynchronous tasks and notifying when all are completed.

• Semaphore (DispatchSemaphore) — for limiting the number of tasks executing simultaneously or for synchronization.

Example of using OperationQueue:

let queue = OperationQueue()

let operation1 = BlockOperation {
    print("Task 1")
}

let operation2 = BlockOperation {
    print("Task 2")
}

operation2.addDependency(operation1) // operation2 will execute after operation1

queue.addOperations([operation1, operation2], waitUntilFinished: false)

Thus, you can flexibly manage parallel execution and dependencies between tasks.