What practices and mechanisms are used to prevent errors when working with multithreaded programs?

To prevent errors in multithreaded programs on iOS and other platforms, the following practices and mechanisms are used:

• Synchronization of access to shared resources: using DispatchQueue (especially serial queues), NSLock, pthread_mutex to prevent data races.
• Using GCD (Grand Central Dispatch): allows managing task queues, simplifying thread management and avoiding direct thread control.
• Avoiding race conditions: designing code to minimize concurrent access to mutable data.
• Using atomic operations: for example, OSAtomic functions or atomic properties.
• Immutable objects: whenever possible, use immutable objects to avoid conflicts during parallel access.
• Thread Sanitizer: a tool for detecting synchronization errors during development.

Example of using a serial DispatchQueue for synchronization:

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

serialQueue.async {
    sharedResource += 1
}

serialQueue.async {
    print(sharedResource)
}

This approach guarantees that operations on sharedResource are performed sequentially, preventing races.