Ahah! We were both looking in the wrong place, as we both only found the declarations, not the definition. With your pointer, I was able to find it though: http

Ahah! We were both looking in the wrong place, as we both only found the declarations, not the definition. With your pointer, I was able to find it though: https://github.com/apple-oss-distributions/libplatform/blob/265976204fef993fd699fb97e874fcc9d5a95e4b/src/os/lock.c#L613 https://github.com/apple-oss-distributions/libplatform/blob/... So perhaps I am wrong. I was always under the impression that you couldn't count on Darwin to be representative of how iOS/OSX work anymore, but maybe I'm wrong.