I've heard of atomic variables and such, and I've wondered. Can anyone please give an explanation?
What are atomics?
Since the Engrs. recommend to link to live Apple info where possible, and avoid paraphrasing, see the 'Threading Programming Guide / Synchronization / Atomic Operations' for discussion. Speak up if you still need clarity, etc.
You didn't mention Swift as a context, but if that was my oversight and not yours...
https://stackoverflow.com/questions/24157834/are-swift-variables-atomic