[slime-devel] Re: interrupt and multiple processes

[Luke Gorrie]

Alan Ruttenberg <alanralanr at comcast.net> writes:

> When there are multiple processes and an interrupt is sent,
> lisp(openmcl in my case) needs to know which process to interrupt.
> So when the interrupt is being processed I need to ask emacs for that
> information before choosing the process to interrupt.
> What's the proper way to do that?

I don't think there is a proper way as of today. The Emacs side has no
notion of threads, so is there anything useful it can tell Lisp at
all?

How will you interrupt a specific thread in OpenMCL? Do they each have
their own OS PID such that you could SIGINT the right one, or is it
necessary to do a (interrupt-thread T) sort of call inside Lisp? (I
think the first will work in SBCL and the second will be needed in
CMUCL).

If the second, a temporary hack could be to have Emacs send
e.g. SIGUSR1 and Lisp have a handler that knows to interrupt the Swank
request-handler thread, or something..

> Also regarding multiple processes: I'm running portable aserve and
> would like to be able to have errors that occur in the server
> processes
> create a slime debugger instance. Is there a way to set that up, given
> that those processes are not associated with a repl?

We have no reliable way to do this. The unreliable (kinda okay with
SERVE-EVENT, probably suicide with threads) is in .emacs:

  (setq slime-global-debugger-hook t)

That way *DEBUGGER-HOOK* will be globally bound to contact Emacs,
always using the same connection, come-what-may. My previous attempt
at multiprocessing support just added locks to this so that only one
thread would talk to Emacs at a time.

But hopefully the multiple-session support will fix all this. Today it
would be possible for Emacs to connect to multiple Swank servers each
run by a different thread in the same Lisp. The trick is just to hack
in support for creating these extra connections on-demand (e.g. when a
thread hits the debugger). I was planning to hack that up on the
weekend if I get time, but you're welcome to beat me to it too :-)

Cheers,
Luke