Date: Thu, 3 May 2012 23:10:01 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: gdb problem
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On Thu, May 03, 2012 at 04:05:04PM -0400, Ken Brown wrote:
>On 10/23/2011 5:47 PM, Ken Brown wrote:
>> On 10/23/2011 3:04 PM, Christopher Faylor wrote:
>>> On Sat, Oct 22, 2011 at 04:37:55PM -0400, Ken Brown wrote:
>>>> The attached testcase illustrates a problem with `gdb -i=mi'. I've
>>>> tested both gdb 7.3.50-1 and 7.3.50-2, with cygwin 1.7.9 as well as with
>>>> several recent snapshots (including 2011-10-22).
>>>>
>>>> Under some circumstances, if gdb -i=mi is started and given several
>>>> input lines at once, it only prints part of the output before stopping.
>>>> I've been able to reproduce this once in a while while working
>>>> interactively (by copying and pasting the whole bunch of input lines);
>>>> in this case one can press Return to get the rest of the output. But
>>>> the problem happens consistently with the attached test case, which runs
>>>> gdb in a subprocess. One has to kill the gdb process before the main
>>>> program exits.
>>>>
>>>> The STC runs as expected on Linux.
>>>
>>> Thanks for the STC. I had to tweak it to actually see how it was supposed
>>> to work on Linux since only a limited number of lines from the pty were
>>> being output. I've included the revised test case below.
>>>
>>> I made a simple change to Cygwin which will probably cause subtle
>>> problems somewhere down the line. At least for now it seems to make gdb
>>> operate as expected.
>>>
>>> I'm building a new snapshot now.
>>
>> Thanks, that fixes it (as well as the emacs problem that originally led
>> to this report). In case there are emacs users wondering what this is
>> about, I've been testing emacs-24, which uses gdb -i=mi instead of the
>> obsolete gdb --annotate=3 used by emacs-23.
>
>I'm replying to this old thread because the problem is back again in 
>cygwin-1.7.14-2.  I haven't checked to see exactly when it first 
>reappeared (but I'll do this if it would help.)  The same STC as before 
>exhibits the problem; I'm attaching it for convenience.

Thanks for the heads up.  This should be fixed in the next snapshot.

Incidentally, I've started putting longer explications of what I've
debugged and how I debugged it in a "DevNotes" file in the source:

http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/DevNotes?cvsroot=src

I hope to keep this up-to-date with extended rationales for why things
were done a certain way and with descriptions about the steps that I
used to track down a problem.

This file is not a substitute for comments (we've been trying to be more
diligent about commenting changes in the source) or a ChangeLog but I
hope that it will help me in the future when I have to figure out "Why
the heck did I make that change?"

cgf

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