I assumed joinable would indicate this, however, it does not seem to be the case.
In a worker class, I was trying to indicate that it was still processing through a
Since you can join a thread even after it has terminated, joinable() will still return true until you call join() or detach(). If you want to know if a thread is still running, you should be able to call timed_join with a wait time of 0. Note that this can result in a race condition since the thread may terminate right after the call.