[AlotOfReading]

I was interviewing at Apple some years ago and was in the final on-site interview with some people from the compiler team. I offhandedly mentioned that std::atomics was allowed to be implemented with mutexes and was in this particular edge case on common platforms while I was explaining some decisions in example code. The interviewer immediately snapped back that it wasn't true. I pointed out is_lock_free(), which they didn't believe existed and offered to look it up to resolve the disagreement (rejected). It went on for several minutes before I could get the conversation onto a new topic, but the interview went from intense to actively hostile for the remainder. All the other sessions went well from my perspective, but that presumably caused a hard no. I still have no idea if there was some other point being made or the interviewer just wasn't familiar with that corner of C++.