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Re: How to get it working with gdb ?
On Sun, 28 Dec 2003, Frédéric L. W. Meunier wrote:
> On Sat, 27 Dec 2003, Christopher Faylor wrote:
>
> > On Sat, Dec 27, 2003 at 07:42:18PM -0200, Frédéric L. W. Meunier wrote:
> > >I did the following:
> > >
> > >Start the application in a terminal.
> > >Use ps in another terminal.
> > >Use gdb -p from that terminal.
> > >
> > >Then:
> > >
> > >(gdb) c
> > >Continuing.
> > >
> > >Do something with the application.
> > >
> > >Then I tried ^C in gdb and it didn't work, but it works on
> > >Linux.
> > >
> > >Sorry, I'm not used to debug things, but I'd like to know why
> > >the above doesn't work.
> > >
> > >I'm trying to investigate the ELinks problem with compressed
> > >files, but it turns out to be a PITA. I can't reproduce it on
> > >Linux, but I guess it'd have worked since ^C does.
> >
> > Type ^C on the console that is running ELinks.
>
> Thanks, I at least got back the gdb prompt, but it always
> returns the same things with a bt, also with other
> applications:
>
> (gdb) c
> Continuing.
>
> Program received signal SIGINT, Interrupt.
> [Switching to thread 1452.0x788]
> 0x77ea31c7 in KERNEL32!GetAtomNameA () from /c/WINDOWS/system32/kernel32.dll
> (gdb) bt
> #0 0x77ea31c7 in KERNEL32!GetAtomNameA ()
> from /c/WINDOWS/system32/kernel32.dll
> #1 0x77f57d70 in ntdll!RtlAppendStringToString ()
> from /c/WINDOWS/System32/ntdll.dll
> #2 0x77f58a3a in ntdll!RtlAppendStringToString ()
> from /c/WINDOWS/System32/ntdll.dll
>
> I compiled ELinks with --enable-debug, which adds -g. Doing the
> same on Linux (c, bt, ^C) always returns lines from the ELinks
> sources.
>
> Well, I uploaded a new trace in case it helps -
> http://www.pervalidus.net/tmp/elinks.txt.gz. It's much smaller.
> I used the latest cygwin1.dll and strace snapshots, strace -p
> -t, and only started it at the time I connected to the URL.
This may be way off-topic (this list is not intended to provide gdb help),
but it looks like a lot of debugging with Cygwin goes beyond rudimentary
gdb capabilities, since, AFAIU, *any* Cygwin program is multi-threaded (in
the Windows sense). For more information on the gdb thread commands,
visit "info -f gdb.info-12 -n 'GDB/MI Thread Commands'". A short summary
is below.
To get the list of threads, use the 'info threads' gdb command, and then
use 'thread NUM' to switch to thread number NUM. Once you're in the right
thread, you can get a meaningful backtrace.
Igor
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