Nobody's arguing that volatile has anything to do with CPU cache, or barriers, or locks, or any other nonsense! volatile is there to ensure that the compiler generates code that accesses the variable directly each time, which is necessary to write correct multi-threaded code. If you don't use volatile, and your code still works, then either the compiler's smarter than you, or you got lucky. End of story. The level of misunderstanding you guys are showing on the matter is beyond comical.

volatile's one of the simplest modifiers to understand if you care to actually learn the language. It has a clear, and well-defined purpouse, and i have no idea how you can spend so much time, and energy arguing that that's not the case.