[cgf: Re: rxvt SEGV (Win98, 1.1.5s/2000-10-08)]

Tue Oct 17 14:30:00 GMT 2000

On Tue, Oct 17, 2000 at 04:52:49PM -0400, Jonathan Kamens wrote:
>> and set
>> CYGWIN=error_start=x:/path/to/gdb.exe . This will cause cygwin to pop
>> up a gdb window when it encounters an error. If you then issue the
>> following commands:
>>>> thread 1
>> bt
>>>> It should be a little clearer what is going on.
>>>> Barring that, strace output would also probably help pinpoint the problem:
>>>> strace -om:/tmp/strace.out make
>>>> (this will probably be a big file) Please do this with the most recent
>> snapshot. That would be 2000年10月16日.
>>Unfortunately, this isn't so simple.
>>* Sometimes when I use the error_start setting you indicated, and the
>error that Cygwin encounters is "c:\cygwin\bin=make.exe: *** couldn't
>send signal 20", Cygwin then hangs rather than popping up a gdb window
>as you described. My only recourse at that point appears to be to
>kill all the running Make processes using the task manager.

If you configure in the winsup directory with '--enable-debugging' this
will cause gdb to pop up when this error occurs.
>* Other times, I get something that looks like this:
>> 0 [sig] make 207 handle_exceptions: exception: STATUS_ACCESS_VIOLATION
> 9124 [sig] make 207 stackdump: Dumping stack trace to make.exe.stackdump
>>What then pops up is a GUI debugger which I've never used before. It
>wasn't obvious, but I eventually figured out that I'm supposed to
>select "View -> Console" and then type the commands you specified in
>the window that pops up. Unfortunately, the output is useless:
>> (gdb) thread 1
> [Switching to thread 1 (process 261)]
> #0 0x0 in ?? ()
>> (gdb) bt
> #0 0x0 in ?? ()
>> (gdb) 
>>Do I need to compile a later version of gdb than 1.1.4 in order for
>this to be useful? If so, where do I get the source code from, or is
>there a precompiled binary somewhere that I can use? Do I need to
>compile cygwin1.dll in a manner different from how I actually compiled
>it?

The gdb that comes with cygwin should be adequate. You can start it up
in just console mode by typing 'gdb -nw'. You'll have to set up a
.bat file to do this:
gdb -nw %1 %2 %3 %4 %5
Then you don't have to use the unfamiliar console.
The other threads may have useful information: 'thread apply all bt'
If all else fails, you can decode the stackdump by typing
l *0x610xxxx (or whatever) in gdb on each address.
> When I run the command under strace inside bash, it produces a 35Mb
>log file and doesn't fail. When I run the command under strace at the
>CMD prompt, it produces about a 1Mb log file and then fails with an
>error message like "strace: Closing child handle 00000038".

This should be fixed in snapshot versions of strace (or if you build
from sources). This error is a problem in strace that has no bearing
on the cygwin problem.
cgf
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