David Baelde a écrit :
> Both liquidsoap and ocaml-duppy are compiled with -threads, so they
> are using the same version of Unix. Duppy is not linked against Unix,
> only requires it through ocamlfind. Could it be that ocamlfind (on
> some versions) links Unix twice in liquidsoap? I did not know it was
> even possible (except with Dynlink).
                 ^^^^^^^^^^^^^^^^^^^

Are you sure Dynlink is not used at all in the circumstances of the bug?

> Also, note that the call to read that raises the error is from the
> same module that tries to catch the exception.

If Jake is right, a call to Unix.read might not be catchable even in the
same module.

> I'm lost, I'd like to understand when the exception is registered: at
> runtime initialization? In this case, only one should ever be
> registered (at least it seems easy to enforce). Or is it statically
> registered somehow?

The exception is registered when the module is evaluated. This can
happen at program startup, or during a call to Dynlink.load_file. Note
that if Unix is linked in a cmxs file and you dynload it, you will face
trouble.

-- 
Stéphane