DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 4B9G9OXN856827
Date: Mon, 9 Dec 2024 17:00:40 +0100
To: cygwin@cygwin.com
Subject: Re: cygpath and unc paths
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From: Corinna Vinschen via Cygwin <cygwin@cygwin.com>
Reply-To: cygwin@cygwin.com
Cc: Corinna Vinschen <corinna-cygwin@cygwin.com>
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On Dec  9 14:48, Federico Kircheis via Cygwin wrote:
> On 09/12/2024 14.17, Corinna Vinschen via Cygwin wrote:
> > On Dec  9 13:47, Federico Kircheis via Cygwin wrote:
> > > 1)
> > > root path, like C:\ , because for whatever reason \\?\C:\ is not valid, it
> > > has to be a subfolder (and trying to trick it with \\?\C:\\ does not work
> > > either).
> > 
> > In which scenario?  \\?\C:\ is just the same as \??\C:\ in NT speak, and
> > that's a perfectly valid directory path.
> 
> I've never seen \??\C:\.

Sorry for any confusion.  \??\ is a symlink in the NT namespace and
only used when calling kernel functions.  It's basically the same
as \\?\ and \\.\ in the Windows namespace, depending on the target.

> My test case, from powershell (which I do definitively _not_ know well
> enough, otherwise I wouldn't be using cygwin) was
> 
> cd C:\             # success
> cd \\?\C:\         # fail
> cd C:\windows      # success
> cd \\?\C:\windows  # success
> 
> and repeat the same operation with dir instead of ls.
> 
> The error message is that the "value of argument path is not valid"
> 
> I did some further testing: no amount of quoting (with ", ' and `) helps,
> also replacing \ with / does not change any outcome.
> 
> For cd, the parameter -literal makes a difference
> 
> cd -literal \\?\C:\  # success

Huh!

> Yes, -wa works; I wanted to point out that DOS paths are not a viable
> workaround.
> I could have left it out from my first mail, we agree no need to iterate
> further ;)

Yeah.  The expression "DOS path" is a bit ambiguous.  We like to use it
to differentate DOS from POSIX paths, no matter if the "DOS path" is in
long or short form.  It's actually a bit puzzeling.


Corinna

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