Two other macos breakages that I've recently been bitten by: They never got round to implementing unnamed posix semaphores: sem_init() will always give EINVAL.

Two other macos breakages that I've recently been bitten by: They never got round to implementing unnamed posix semaphores: sem_init() will always give EINVAL. They never got round to finishing poll(). It fails on devices. Because this includes /dev/null, it can make using poll() on stdin and stdout in general-purpose command-line tools dangerous. It used to fail on pipes too, but possibly this is now fixed?