Exactly. I mentioned that those queues aren't formally obstruction-free because the context of the conversation was new developments in wait-free queues, even though I have only needed the guarantee once in my career and end up using descendants of the Vyukov MPMC cycle queue in practically all other cases because they are better on the metrics that count, like speed.

What was the one time when you need something wait free? I'm assuming interacting with hardware?

Hard real-time industrial automation. Worst job ever, by the way.