RE: [rms@gnu.org: Re: [twurgler@goodyear.com: emacs-21.2.90 on HP 11.0]]

[WAROQUIERS Philippe <philippe.waroquiers@eurocontrol.int>]

    !!!  if (inchannel >= 0)
	{
    #ifndef USG 
	  /* On USG systems it does not work to open the pty's tty here
		   and then close and reopen it in the child.  */

  What happens if you change USG to 0 in that conditional?
  Does subtty get set up properly?  Does everything work after that?

I suppose that what you wanted is to execute the code inside the #ifndef
so I have replaced
#ifndef USG
by
#ifndef THIS_IS_NOT_DEFINED
(replaced USG by 0 was giving a compilation error).

After this, the following works properly:
M-x shell
cat
C-c C-c
(or Signals -> Break)
Note however that it is still needed to initialise int gid = 1;
in process_send_signal to have C-c C-c killing the cat. If I remove
the initialisation of int gid; then C-c C-c does not work while
Signals -> Break works.


  Also, independent of that, if you take away the #if 0 that currently
  surrounds these two lines, and make them unconditional,

	if (err == -1)
	  gid = - XFASTINT (p->pid);

  does that fix the problem?
(NB: in emacs-21.2, it is not #if 0 
but #ifdef pfa).

Yes, it also fixes the problem. But I think this is just another way to put
any value in gid which makes the rest of the code work.
If I put gid = 12345; it works as good as if I put  gid = - XFASTINT
(p->pid)
The ioctl TIOCPGRP still fails (err = -1, errno= 25 ENOTTY).
But any value in gid is ok because when TIOCSIGSEND is defined, gid is only
used afterwards to compare to -1.
After, when TIOCSIGSEND is defined and current_group is not nil, gid is 
unused to send the signal.