Can you explain what a mutual exclusion mechanism (Mutex) is and how it works to prevent simultaneous access to resources?

The Mutual Exclusion Mechanism (Mutex) is a synchronization method that guarantees that only one thread or process can access a shared resource at any given time.

How it works:

• Mutex provides a lock that a thread must acquire before using the resource.
• If another thread has already acquired the mutex, subsequent threads will wait for it to be released.
• After finishing with the resource, the thread releases the mutex, allowing others to access it.

This prevents race conditions and ensures data integrity during concurrent access.

Example in Swift (iOS):

let mutex = DispatchSemaphore(value: 1)

func accessResource() {
    mutex.wait() // acquire mutex
    // work with shared resource
    mutex.signal() // release mutex
}

Here, DispatchSemaphore with an initial value of 1 acts as a mutex.