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Date: Fri, 29 Jun 2001 16:53:52 -0400
From: Christopher Faylor <cgf AT redhat DOT com>
To: cygwin AT cygwin DOT com, gdb AT sources DOT redhat DOT com
Subject: Re: gdb run < file
Message-ID: <20010629165352.B8545@redhat.com>
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In-Reply-To: <2427-Fri29Jun2001101154+0300-eliz@is.elta.co.il>; from eliz@is.elta.co.il on Fri, Jun 29, 2001 at 10:11:54AM +0300

On Fri, Jun 29, 2001 at 10:11:54AM +0300, Eli Zaretskii wrote:
>> Date: Thu, 28 Jun 2001 22:06:02 -0400
>> From: Christopher Faylor <cgf AT redhat DOT com>
>> 
>> I'm sorry but I don't think that this is the correct way to deal with
>> this.  I think that gdb normally handles things like redirection and
>> globbing by starting inferior processes via the user's shell.  Then it
>> uses some kind of "follow fork" method to notice when the process is
>> finally started.
>
>I don't know anything about Windows debugging interface, but it might
>be that putting a shell between the debugger and the debuggee breaks
>something.
>
>Going through the shell also has the limitation that you buy whatever
>idiosyncrasies there are in that shell.  Unlike on Unix, where the
>redirection behavior is quite similar between the shells, on Windows
>there's a very wide disagreement.  (We are fed up with that nuisance
>in the Emacs-land.)  So I think there's a lot of sense in having a
>unified, predictable redirection support inside GDB that doesn't
>depend on the queer shell the user happens to have.

Since Cygwin is supposed to emulate Windows, there shouldn't be much
difference between the way UNIX does it and the way Cygwin does it.
All of the shells come from UNIX, anyway.

So, if this is an issue then it must be an issue for UNIX as well.

>FWIW, the DJGPP port of GDB does something very similar to the patch
>we discuss here (except that it also has to flip redirections every
>time the execution thread jumps from the debugger to the debuggee).
>See go32-nat.c (the actual implementation of the redirection routines
>is in the DJGPP debug support library).

win32-nat.c already has a lot of gratutitous differences with the rest
of the "Unix" code in gdb.  I want to be moving in the direction of
making the cygwin parts more unix-like.  So, I would rather that the
redirection follow UNIX rather than attempting to reimplement the
already implemented.

This is, of course, a problem for running a windows-only version of
gdb but I don't know of anyone currently working on that.  Maybe
we need a separate option for when a complete cygwin system isn't
installed.  However, that would be secondary to getting something
working with /bin/sh or whatever.

cgf

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