Multiple debugging sessions [was Re: `overlay-arrow-position' should be automatically buffer-local]

[Nick Roberts]

 > > It's come up at least twice before.  I rarely debug two programs at the
 > > same time and when I do, I can do it with two instances of Emacs.
 > 
 > This is OK as a temporary workaround before the release, but I think
 > it's unacceptable in the long term -- I, at least, want to debug
 > multiple programs routinely, and it's very inconvenient to juggle
 > multiple emacs sessions to do so.

I can understand that it's not as ideal as working with one instance.  Could
you please explain, in practical terms, what makes it "very inconvenient".

After the release, I want to migrate Emacs from using annotations to using
GDB/MI, since this is the new interface for GDB and the GDB developers
plan to obsolete annotations.  I also want to help make GDB asynchronous
so that front ends can be event driven rather than work by polling.  I'm
afraid that managing multiple debugging sessions is low down on my list
of things to do... unless, of course, someone offers to pay me to do it!

 > > For those that
 > > need multiple debugging sessions there's a note in the Emacs manual to use
 > > "gdb -fullname"
 > 
 > I recall that before gdba, this was the default; why was it changed?

It wasn't changed.  The mode that I've written is almost completely different
to what was there before.  If you only have rudimentary features, it's a lot
easier to be general.

Nick