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Date: Wed, 4 Feb 2026 23:50:22 +0100
Message-ID: <CAAvCNcBSozq08ASWx6c-M8QB7aPz6tRx+Cqk8wz-1x=y0u_e5g@mail.gmail.com>
Subject: Re: Why does Cygwin always use absolute paths instead of
 OBJECT_ATTRIBUTES.RootDirectory?
To: cygwin AT cygwin DOT com
From: Dan Shelton via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Dan Shelton <dan DOT f DOT shelton AT gmail DOT com>
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On Wed, 4 Feb 2026 at 22:37, Brian Inglis via Cygwin <cygwin AT cygwin DOT com> wrote:
>
> On 2026-02-04 14:17, Dan Shelton via Cygwin wrote:
> > Why does Cygwin always use absolute paths instead of
> > OBJECT_ATTRIBUTES.RootDirectory in NtOpenFile(),
> > NtSetInformationFile() for rename and hardlinks
> >
> > This slows down Cygwin path lookups a lot, and with lots of path
> > elements each lookup with a relative RootDirectory might be a lot
> > faster, e.g. for openat(), linkat(), renameat().
>
> Because volunteers' spare time is limited, and performance is good enough for
> those who might do the work:

Please do not slap me. That hurt.

My question is about whether there are any technical issues which
prevent OBJECT_ATTRIBUTES.RootDirectory from being used in Cygwin for
openat().

2nd question: Is OBJECT_ATTRIBUTES.RootDirectory really a root, and
you cannot do cd ..?

Dan
-- 
Dan Shelton - Cluster Specialist Win/Lin/Bsd

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