macOS has a thread_info() call that will let us know whether a thread is running or waiting. We can call it with THREAD_BASIC_INFO and that will give us the following information: run_state: TH_STATE_RUNNING The thread is running normally. TH_STATE_STOPPED The thread is stopped. TH_STATE_WAITING The thread is waiting normally. TH_STATE_UNINTERRUPTIBLE The thread is in an un-interruptible wait state. TH_STATE_HALTED The thread is halted at a clean point. sleep_time: We can use this to differentiate multiple calls to the same waiting function and record. Unfortunately, it's only in seconds so might not be that helpful.