How can I wait for any/all pthreads to complete?

I just want my main thread to wait for any and all my (p)threads to complete before exiting.

The threads come and go a lot for different reasons, and I really don't want to keep track of all of them - I just want to know when they're all gone.

wait() does this for child processes, returning ECHILD when there are no children left, however wait does not (appear to work with) (p)threads.

I really don't want to go through the trouble of keeping a list of every single outstanding thread (as they come and go), then having to call pthread_join on each.

As there a quick-and-dirty way to do this?