NSNotificationCenter is thread-safe NOT

from blog The Desolation of Blog, | ↗ original
According to Apple's Threading Programming Guide, NSNotificationCenter is a thread-safe class. "You can use the same instance from multiple threads without first acquiring a lock." However, this is extremely misleading. In fact, if your app has multiple threads, then you're almost certainly using NSNotificationCenter wrong. Almost everyone makes the same mistake: