Re: MI handshaking

[Bob Rossi <bob at brasko dot net>]

On Fri, Nov 19, 2004 at 02:23:13PM -0500, Bob Rossi wrote:
> On Wed, Nov 17, 2004 at 08:35:32PM -0500, Alain Magloire wrote:
> > > 
> > > On Wed, Nov 17, 2004 at 10:17:57AM -0500, Alain Magloire wrote:
> > > > > 
> > > > > On Sat, Nov 13, 2004 at 10:57:33AM +0200, Eli Zaretskii wrote:
> > > > > > > Date: Fri, 12 Nov 2004 17:57:30 -0500
> > > > > > > From: Andrew Cagney <cagney@gnu.org>
> > > > > > > Cc: Bob Rossi <bob@brasko.net>, Nick Roberts <nick@nick.uklinux.net>,
> > > > > > >         gdb-patches@sources.redhat.com
> > > > > > > 
> > > > > > > > =mi-handshake,versions=[mi1,mi2,mi3],stable=[mi2]
> > > > > > > 
> > > > > > > Yes, thanks for the correction with ``=''.   But not 
> > > > > > > ``versions=[mi1,mi2,mi3]'' that's too much and misleading information.
> > > > > > > 
> > > > > > > I think the objective here needs to be to provide as much information as 
> > > > > > > possible about what version of GDB and MI is running.  Hence the:
> > > > > > > 
> > > > > > > 	version="mi2"
> > > > > > > 
> > > > > > > (where hopefully VERSION version is a member of STABLE :-)
> > > > > > 
> > > > > > We've been through this discussion, and the only suggestion that
> > > > > > brought a consensus was to print all the supported MI versions, not
> > > > > > just one.  Let's not reopen that discussion again, even if the result
> > > > > > looks ``too much and misleading''.  (Why ``misleading'', btw?)
> > > > > 
> > > > > Yeah, anyways it doesn't really matter for now. GDB only supports one
> > > > > version, and I have a feeling it will stay that way for a long time.
> > > > > 
> > > > 
> > > > sigh ... sorry for being dense (hopefully this will not be a long thread)
> > > > but why are you keep on saying: "GDB only supports one version"
> > > > for example, I have gdb-6.1.x and I can start
> > > > # gdb -i mi1
> > > > # gdb -i mi2
> > > > # gdb -i mi3
> > > > 
> > > > that it is more then one version?
> > > 
> > > oops, sorry, I meant to say that GDB supports only 1 stable MI version.
> > > This is only relavent when discussing what GDB should do when the user
> > > starts with 'gdb -i=mi'.
> > > 
> > > I see 2 needs stemming from this patch.
> > >    
> > >    - I need the handshaking to happen before any other I/O.
> > >      This allows my front end to determine the protocol that is going to
> > >      be used by GDB.
> > > 
> > >    - Alain, it seems like you need this command to be available after
> > >      the fact. Even though this seems unintuitive to me, I understand
> > >      that it's not a perfect world, and this info could be useful later
> > >      on, especially if you are not responsible for staring GDB.
> > > 
> > 
> > Yes.
> > Very true, it is not a perfect world but I also think it is rather inconsistent
> > that important information is lost once the screen scrolled away,
> > i.e. no way to retrieve it, beside restarting ...
> > 
> > > It seems as if there is two parts to this patch. The first part does the
> > > handshaking, and that takes care of the protocol that should be used.
> > > Here, GDB will give all of the info necessary to help the front end determine
> > > the protocol that it wants to use. For instance, the protocols possible,
> > > the build date, the GDB version, ...
> > > 
> > > Also, as a second part, a new MI command could be added, that simply
> > > repeats all of the info determined from the handshaking functionality.
> > > This would allow front ends to query the information later on, if for
> > > some reason it couldn't do it originally. Note however, this would not
> > > repeat the handshaking, and the version of MI being used can not be
> > > changed. 
> > > 
> > 
> > Yes.
> > I did not advocate to be able to change MI versions at runtime.
> > That would be overkill, i.e. it would be simpler to restart gdb
> > then to try to code that complexity with little benifits, IMHO
> > 
> > > Would this be OK for everyone?
> > > 
> > 
> > That would be good, and the proposed format suits me fine
> > mi-version="mi2",...
> > 
> > Thanks Bob for looking at this.
> 
> I've been very busy, so sorry about the delay.
> 
> I'll look into what we discussed here and come up with something that
> fits all the new needs. Does Jim care about any of this?

Sorry about the delay.

I plan on getting at least this patch into GDB. So, to recap, I neede to add 
a new mi-command that would output all of the info discovered during the 
handshaking phase. Is there anything else that needs to be added?

Thanks,
Bob Rossi