MI threads behaviour

Daniel Jacobowitz drow@false.org
Wed Jul 16 12:11:00 GMT 2008


On Wed, Jul 16, 2008 at 03:51:00PM +0400, Vladimir Prus wrote:
> On Thursday 10 July 2008 01:03:11 Daniel Jacobowitz wrote:
> > On Wed, Jun 18, 2008 at 04:01:52PM +0400, Vladimir Prus wrote:
> > > The CLI behaviour of setting GDB current thread to invalid value if the
> > > current thread exits will be preserved, but is of limited value, since 
> > > the frontend does not depend on current thread directly, and will be notified
> > > about thread exit anyway. Therefore, no notification will be emitted in
> > > this case.
> > 
> > What about in all-stop mode, where the CLI behavior is to change to a
> > new event thread?
> 
> We're talking about thread exit here -- does CLI automatically switch to a non-dead
> thread when the current one exits? If so, then the notification would have to
> be emitted, too.

It doesn't do anything when the thread exits - it's blocked in wait.
But at the next stop it will select the event thread.

> > > The notification will be emitted even if the thread user requested to be
> > > selected is the same as currently selected thread. Imagine the frontend
> > > has two windows open -- in one, UI has thread 1 selected, and in another,
> > > UI has thread 2 selected. If user types "thread 2" in GDB console in the
> > > first window, would expect the first window UI to switch to thread 2. So,
> > > the notification should be emitted even if GDB current thread is 2, 
> > > already.
> > 
> > I don't understand the need for this.  If you're going to let the user
> > type a CLI command, then before you can do that you have to make sure
> > GDB and the UI are synchronized on the current thread/frame.
> > Otherwise "backtrace" or "thread" won't work.
> 
> What is "synchronized"? You don't need to emit -thread-select, since there's
> --thread, and what I mean is that if have a window where UI's selected thread
> is 1, and you type "thread 2" in console, and frontend sends
> 
>    -interpreter-exec --thread 1 "thread 2"
> 
> then one should get
> 
>    =thread-selected,id="2"
> 
> regardless of what inferior_ptid was immediately before this command is processed.

You'd get a notification there but only because we changed from thread
1 to thread 2 inside the command.  For the purposes of that command,
the "currently selected thread" is thread 1.

This is the command I don't think should get a notification:

  -thread-select 2
  -interpreter-exec --thread 1 console "thread 1"

-- 
Daniel Jacobowitz
CodeSourcery



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