Whether it's a justified choice or not, for whatever reason, POSIX semaphores are very rarely used. macOS does not even support them (except for the named ones

Whether it's a justified choice or not, for whatever reason, POSIX semaphores are very rarely used. macOS does not even support them (except for the named ones used for IPC). So pthread_cond_t is certainly 'the' API in terms of actual usage. (Personally, I like events, but sometimes I want ones that don't reset - as in, the event is only ever flipped once in its lifetime, from "not ready" to "ready", but any number of consumers can check if it's ready or wait for it to be ready. These can't be directly implemented with POSIX semaphores. But then, I didn't know until just now that fast POSIX semaphore implementations even existed – there's my Apple bias.)