[Openmcl-devel] Unix signal handling

[Scott L. Burson]

On Mon, Jul 5, 2010 at 8:46 PM, Gary Byers <gb at clozure.com> wrote:
>
> There isn't any general way of defining signal handlers in CCL.  The issue
> comes up every few months on this list, and the response is usually "yeah,
> we should offer that.  Someday."  It's almost certainly doable, but there
> are
> threads/GC issues that make the implementation complicated.
>
> Additionally, the implementation of things like PROCESS-INTERRUPT and the
> mechanism that the GC uses to suspend/resume other threads involves sending
> signals between threads; on some platforms (Darwin), the implementation uses
> SIGUSR1 and SIGUSR2 and possibly something else that the OS never raises,
> and
> it's not clear that there are any leftover unused signal numbers ...

Well, I do need this to work on Darwin, but I think I could get away
with commandeering SIGTTIN and SIGTTOU, if the thread/GC issues could
be dealt with.

Anyway, thanks for the reply.  I see this would be nontrivial.  Let me
try to do what I need to do in a different way.

-- Scott