What are the ways to manage mutual exclusion and synchronized execution of threads in multithreaded programming?

In multithreaded programming, various mechanisms are used to manage mutual exclusion and thread synchronization:

• Mutex (mutual exclusion) — an object that allows only one thread to execute a specific section of code at a given time, preventing data races.

• Semaphore — a counter that limits the number of threads executing a particular code segment simultaneously.

• Dispatch Queues (GCD queues in iOS) — enable organized sequential or parallel execution of tasks. A serial queue guarantees that tasks are executed one after another, ensuring synchronization.

• NSLock, NSRecursiveLock, NSCondition — classes from Foundation for locking and waiting on conditions.

• OperationQueue and Operation — higher-level mechanisms for managing dependencies and task synchronization.

Example of using DispatchQueue for synchronization:

let serialQueue = DispatchQueue(label: "com.example.serialQueue")

serialQueue.async {
    // This code will execute sequentially, without concurrent access
    print("Executing task 1")
}

serialQueue.async {
    print("Executing task 2")
}

Thus, mutexes or serial queues are often used for mutual exclusion, while semaphores, conditions, and dependency queues are used for synchronization.