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Re: gdb problem

On 5/3/2012 11:10 PM, Christopher Faylor wrote:
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.

Confirmed. Thanks.

Ryan, if you're reading this, the problems you were seeing with M-x gdb in emacs should be fixed now.

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

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?"

Great idea. It's also useful for people like me who like to understand what caused a problem they reported and how it got fixed.


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