Question

@property (atomic, retain) NSArray *array;

I don’t override a setter and a getter of the array. I could use @synchronized(array){} or @synchronized(self.array){}. As I knows all cases are correct, am I right?

Answer 1

As you’ve phrased the question, both statements are equivalent as a matter of concurrency safety strategy.

Depending on the scale and how far you have completed work on your project, you may wish to consider an alternative strategy for thread-safety altogether.

Recently, Apple has made a point of recommending thread-safety-by-serialization rather than traditional blocking. In short, as contention increases, serialized access is far more efficient than blocking with @synchronize.

Rather than synchronize, consider setting up a GCD serial queue and queuing up access to resources shared across threads.