How can race conditions be eliminated when working with threads concurrently using GCD?

In GCD (Grand Central Dispatch), to eliminate race conditions when working with concurrent threads, synchronization of access to shared resources is used. The main approaches are:

• Using serial queues: if all operations with a shared resource are performed on a single serial queue, they will execute one after another, preventing simultaneous access.

• Using barrier blocks in concurrent queues: barrier blocks ensure that all previously scheduled tasks complete before the barrier block begins, and subsequent tasks start after its completion.

Example of using a serial queue to protect a resource:

let serialQueue = DispatchQueue(label: "com.example.serialQueue")
var sharedResource = 0

func incrementResource() {
    serialQueue.async {
        sharedResource += 1
        print("Resource incremented to \(sharedResource)")
    }
}

Thus, operations on sharedResource will not be executed simultaneously, preventing race conditions.