* Jonathan Bryant:

> I'm confused as to why the attached code hangs.  My understanding of
> Unix.fork () is that it completely clones the current process, which in
> my understanding, clones the processes's threads as well.  Apparently,
> though, that is not the case, because I can't join the thread in both
> the parent and the child.

I can't speak for the OCaml run-time, but POSIX fork only duplicates
the current thread, so the new process is essentially single-threaded.