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Message-ID: <18e501c19f12$14c13a80$0200a8c0@lifelesswks>
From: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
To: <cygwin-developers AT cygwin DOT com>
References: <18c301c19f0c$7176a770$0200a8c0 AT lifelesswks> <20020117041203 DOT GA5805 AT redhat DOT com> <18cf01c19f0e$13242920$0200a8c0 AT lifelesswks> <20020117043100 DOT GA6071 AT redhat DOT com>
Subject: Re: tty and the cygwin server
Date: Thu, 17 Jan 2002 15:47:33 +1100
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----- Original Message -----
From: "Christopher Faylor" <cgf AT redhat DOT com>


> On Thu, Jan 17, 2002 at 03:18:52PM +1100, Robert Collins wrote:
> >
> >===
> >----- Original Message -----
> >From: "Christopher Faylor" <cgf AT redhat DOT com>
> >
> You have to set some break points.  You're single stepping in an
unknown
> location in an unknown thread.

I'm aware of that :}. Thats why I tried stepi - which should work
regardless.

> You probably also have to switch to the correct thread.  It may be
> thread 1 but with ttys there are more threads involved.

There are three threads active - all in system

thread 1688.0x694  0x77f7f571 in _system_dlls__ ()
thread 1688.0xc38  0x7ffe0304 in ?? ()
thread 1688.0xccc  0x7ffe0304 in ?? ()

> info threads will display the thread.  "thread 1" will switch to
> it.  "bt" will show a back trace.  It's possible that the back trace
> will be inaccurate in some cases due to system dll "frame pointerless"
> functions.

Yep. thread 1 and 3 has that problem, the other one shows
#0  0x7ffe0304 in ?? ()
#1  0x77e74c70 in _system_dlls__ ()
#2  0x61006285 in thread_stub (arg=0x610a6930)
    at ../../../../../src/winsup/cygwin/debug.cc:98

> >Program exited with code 0200400.
> >
> >                      ^ ^^^^^^^^^^^^
> >How should this code be interpreted?
>
> dcrt0.cc: do_exit()

Ok that helps a bit, it's exiting with REPARENTING set (which is very
weird as sh should be vforking, not using _P_OVERLAY), but I still don't
grok 0x400 as a exit value. it seems a little large:}.

> >
> >(gdb) attach 2652
> >Attaching to program `/bin/sh.exe', process 2652
> >[Switching to thread 2652.0xbb0]
> >(gdb) stepi
> >0x77f970a4 in _system_dlls__ ()
>
> 0x77* is a system DLL.
>
> I think the command is "info shared" to list DLLs but since my cygwin
> installation is currently hosed, I can't check.

It's in ntdll.dll, the kernel API gateway.

Rob