http://atfykf7jyn4uxuwdqmonyz4xohrw5mrnrldkwtulxkpictxrm3xxfsyd.onion/@tylerneely/fear-and-loathing-in-lock-free-programming-7158b1cdd50c
It is impossible to witness a half-complete atomic operation. Examples of things that are atomic are database transactions ( but not always as you expect ), the mv command found on most unix-like systems, breaking a glass window (it’s either broken or not, never something in-between), etc… Several of the most popular CPU architectures have instructions that let you atomically set memory to a new value conditionally if you know the current value.