[slime-devel] Shutting down Swank within an Image.

[Nikodemus Siivola]

On 4 November 2011 19:24, Andrew Myers <asm198 at gmail.com> wrote:

> Is this a problem in Lisp?  I know in C that's an issue since you're
> just calling close on an integer but I had thought lisp would handle
> that more gracefully.  Although I guess the behavior isn't specified
> since saving an image is outside the spec?

Well...

It is possible that your implementation keeps track of all open
"system" streams, and cleans up such objects on its own when you save
a core. I would not know if it does that, but I would not rely on it
either.

If it doesn't do that, at some point closing a socket means calling
close(2) or equivalent system call on the file descriptor / handle --
which means is risky on init.

> The problem with cleaning up _before_ saving the image is that you
> can't use the image any more.  I was hoping to have a solution that
> didn't require an exit and restart every time an image was dumped.

Unless you're on Windows, the time honored solution is to fork(2) before saving.

If you can't do that, then digging into implementation specifics you
may be able to nuke the connections without closing the file
descriptors / handles.

...or you can just live dangerously. Just be aware that you're doing
something potentially tricksy, so that if and when something
mysteriously breaks down the road, you know where to look. :)

Cheers,

 -- Nikodemus