Re: MI: asynchronous operation details

[Bob Rossi <bob@brasko.net>]

On Tue, Nov 22, 2005 at 03:20:23PM +0300, Vladimir Prus wrote:
> On Tuesday 22 November 2005 15:12, Bob Rossi wrote:
> > On Tue, Nov 22, 2005 at 11:30:04AM +0300, Vladimir Prus wrote:
> > > Hi,
> > > so, in MI mode if I emit "-exec-continue" gdb starts inferiour and
> > > immediately gives me back the prompt, accepting further commands.
> > >
> > > However, I can't:
> > > 1. Understand what commands can meaningfully be issued while the inferior
> > > is running. Say, all data read/write commands are likely to produce
> > > inconsistent results if inferior is running.
> > > 2. Practically figure out which commands can be issued at all. Say, both
> > > -data-evaluate-expression and -exec-continue just hang, returning
> > > nothing. This is with CVS HEAD.
> > >
> > > Do I understand correctly that asynchronous MI just don't exist in CVS
> > > HEAD, and only command prompt loop is asynchronous? Even if so, and fully
> > > asynchronous MI is coming, what's the answer to question (1) above?
> >
> > This is a feature that does not currently work. However, it's possible
> > that Nick Roberts work will address some of this lack of functionality.
> > If not, I'm sure in the future, either I (you) or someone else will
> > eventually get this working.
> 
> Ok, but -- why do I ever want to issue commands while inferior is running? For 
> which kind of commands is that useful?

You could interupt the inferior, to tell it to stop. I think that would
be equivalent to typing ^c at the console now. Also, you could ask 
GDB if it is currently busy, to determine if you can send another
command. That way, you wouldn't have to keep track of the state of GDB,
you could just always ask it what it's state is.

I'm sure there are other useful features also. However, I agree, it
doesn't seem to be necessary. It's just better.

Bob Rossi