Re: bug in gdb tty command on cygwin

[Steven O'Brien <steven.obrien2@ntlworld.com>]

Chris Faylor wrote:
>[Reply-To set to gdb mailing list]
>On Sat, Jan 04, 2003 at 09:44:05AM +0000, Steven O'Brien wrote:
>>Hi
>>I submitted a patch to fix a bug in cygwin gdb to the gdb-patches list
>->see:
>>http://sources.redhat.com/ml/gdb-patches/2002-12/msg00761.html
>>
>>However, this did not attract any response. What is the next step in
>>getting this patch into gdb?
>
>Patience?

Thanks for your swift response Chris :)

>>With this patch I am able to build and run a fully functional anjuta
>IDE>on cygwin-xfree86. Without it anjuta's debugger will not work on
>cygwin.>I am sure that other X11 GUIs for gdb on cygwin would also
>benefit from>this patch.
>>
>>The patch moves one line of code in just one file that is only used in
>>the cygwin build; and code that is only invoked if the --tty option or
>>tty command are invoked.
>
>I saw your patch but since it invoked a "Huh?" response, it required
>some study.  I don't see any correlation between your description of
>the problem and your proposed patch.  I don't know why closing the tty
>later would cause the kind of problem you were talking about, so it
>isn't an obvious "plop it right in" kind of patch.
>
>cgf

You are right, the problem should not logically occur because of this.
However, the problem is real is is cured by my patch. In any case,
closing the tty after Create Process is logically incorrect, because the
inferior then inherits this fd which could concievably change its
behaviour. My patch therefore is a correction for an error in the gdb
code. As a bonus, the patch also fixes the broken gdb tty command, which
is what I need for cygwin-xfree86 anjuta.

After more testing, I have found that the problem does not occur when
the target tty is a windows console running bash. It does not matter
whether gdb is running in a console or pseudo-terminal. My testing
previously had used only rxvt (both X11 and native windows), xterm and
gnome-terminal, all of which cause the failure. I guess this might
indicate some problem with cygwin pty code. But the gdb tty command has
been broken for a long time, so its unlikely that the recent cygwin tty
changes are to blame.

Thanks again for looking at this,
Steven