Re: invoking GDB from FE and signals

[Bob Rossi <bob_rossi at cox dot net>]

On Mon, May 15, 2006 at 12:05:22PM -0700, PAUL GILLIAM wrote:
> On Mon, 2006-05-15 at 15:43 -0400, Bob Rossi wrote:
> > On Mon, May 15, 2006 at 03:17:14PM -0400, Daniel Jacobowitz wrote:
> > > On Mon, May 15, 2006 at 02:18:21PM -0400, Bob Rossi wrote:
> > > > OK, here's what happens from the FE perspective though. You type ^c. The
> > > > FE get's the signal (which is in a different process group than GDB),
> > > > and passes the signal to GDB with 'kill (gdb_pid, SIGINT)'.
> > > 
> > > Jim just explained this, but it may not have been clear: that is the
> > > wrong way to forward the signal.  If you are running GDB on a
> > > pseudo-tty, you need to forward the job control signal to that TTY, not
> > > to the GDB process itself.
> > > 
> > > I don't really know how to do that.  Is it by setting BRKING in
> > > termios?  There's something about TIOCSIGNAL too.  Lots of code for
> > > this in emacs.
> > 
> > I'm totally confused. I'm certainly not an expert, but sending a signal
> > can only be done to a pid using kill. What other ways are there?
> > 
> > Bob Rossi
> 
> Two things:
> 1) Yes the only way to send a signal to a *pid* is with kill.  But which
> pid?  DO NOT SEND THE SIGNAL TO GDB!  Send it to GDB's inferior.  

haha. See, pedantic is good. I'm catching on. Now, please forgive me for
asking. Is it as easy as sending the signal to the inferior all the
time? or do I need to send it to the inferior when it is running, or to
GDB when it is running?

and is that why it's better to somehow send it to the PTY? I'm thinking
just writing the ^c to the PTY is the best solution, since it will
handle all of this for me.

> 2) Danial is not asking you to send a signal to a pty, he is asking you
> to send a signal to GDB's inferior *via* the pty, by using an ioctl
> function and suggesting that code exists in EMACS to do just that.

Whoa, that's interesting.

Thanks,
Bob Rossi