Is it possible to use a standard dictionary as a thread-safe data structure in a multithreaded environment?

The standard dictionary in iOS (for example, Dictionary in Swift or NSMutableDictionary in Objective-C) is not thread-safe. This means that concurrent access from multiple threads without synchronization can lead to data races, structure corruption, or crashes.

If you need to use a dictionary in a multithreaded environment, you should provide external synchronization, for example, using:

• Queues (DispatchQueue) with barriers or serial access.
• Mutexes or other synchronization primitives.

Example of using DispatchQueue for safe access:

let queue = DispatchQueue(label: "com.example.dictionaryQueue")
var dict = [String: Int]()

// Writing
queue.async(flags: .barrier) {
    dict["key"] = 42
}

// Reading
queue.sync {
    let value = dict["key"]
}

For high-load scenarios, specialized thread-safe data structures can be used.