Re: How does GDB/MI give the current frame

["Alain Magloire" <alain at qnx dot com>]

> 
> >  > > For the CLI, something like this:
> >  > > 
> >  > > -> -interpreter cli "up"
> >  > > <- ~"info on new frame..."
> >  > > <- *select-frame,<frame-info>...
> >  > > <- done
> 
> Note that the interpreter case is key, it lets the GUI respond to 
> operations on the command line.
> 

Absolutely!!

> >  > One thing:
> >  > 
> >  > -thread-select 2
> >  > ^done,...
> >  > -stack-select-frame 3
> >  > ^done
> >  > -thread-select 1
> >  > ^done,..
> >  > -thread-select 2
> >  > ^done,..
> >  > 
> >  > If you would do "-stack-info-frame" now, you would notice that current
> >  > stackframe for thread 2 is not longer frame 3 but frame 0 !!
> >  > It this case would not it be appropriate to fire a "*select-frame" event.
> > 
> > There would still be problems with displaying the values of variables.
> > Neither variable objects or the CLI command, display, seem to take
> > notice of the thread number.
> 

Nic, are you using the -var-obj for variables, in theory they
have the context i.e. should be thread aware ?

> ``bug'' in current MI protocol.  How would something like:
> 
> -thread 2 -<something else>
> ^done
> -thread 2 -frame 3 -<something else>
> -frame 3 -<something else>
> ^done
> 
> grab you?   ``-thread'' and ``-frame'' select the thread/frame for 
> _just_ the period of that command.  They would not alter the CLI's 
> selected thread/frame (the implementation would for the moment need to 
> be a crock but thats a separate problem :-).
> 
> This would let the GUI manipulate frames independant of the CLI.
> 
> > Second thing:
> > Playing with MI, I've notice in between -var-update|-var-delete|etc ..
> > operation the frame selection level was reset to 0, failing the other operations
> > that was still assuming a certain frame level.
> > Now is this an appropriate behaviour? or a bug? if it is appropriate should
> > client recall -stack-select-frame XX all the time to make sure things are ok
> 
> ``bug''.  Actually major screwup in how GDB models threads (as in it 
> doesn't really :-)
> 

8-) ok.

> > How about to put the thread-id part ot the event ?
> 
> So the event would be ``selected changed'' and generated when both 
> switching threads and frames?  If it is useful, ok.
> 

If you are asking if we would want an event for thread selection
the same as for frame selection ...  The answer is a strong "Yes".

Our problems is coordinating the mix of CLI and UI driven actions
so things are in sync.  So if the user select a new thread via
the command line, variables and all othe related views should be updated.

The hard lesson learn from the last CDT/Debug release, is that the 
command prompt will stay and the users(allthough not a majority) that
wanted this feature ... are __very__ vocal.