From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <rene.berber@gmail.com>
Received: from mail-ot1-x32a.google.com (mail-ot1-x32a.google.com
 [IPv6:2607:f8b0:4864:20::32a])
 by sourceware.org (Postfix) with ESMTPS id 63189385DC1B
 for <cygwin@cygwin.com>; Wed, 15 Apr 2020 18:30:27 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 63189385DC1B
Received: by mail-ot1-x32a.google.com with SMTP id e20so896243otl.2
 for <cygwin@cygwin.com>; Wed, 15 Apr 2020 11:30:27 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:subject:to:references:from:message-id:date
 :user-agent:mime-version:in-reply-to:content-language
 :content-transfer-encoding;
 bh=QiQrwD894VO47zvd+rHLLOx8E3HSirJ33uxpiiBks0I=;
 b=tEVT7TDmwTqypPNHGhIx2zPrvK+jQwRmsskJMUi/uTuGUUOPAjF2d6wC+QncZfRxyx
 FZjv8bJLyEBPs4x3XcopJ6+HUqe1wtZoABshCoEVO8nhJs7yfqe0JPF/yq61GcMIs9X1
 lEHCTpSRMCEl+XAzWa7ryhCV3WR4b3C8OOkWSP28w9DMC7JX77BSihkYijIq5/ggL+rM
 29Lgf5gTQngXM0NWNKcTIFQZxPAQWzfrvNrg57VIC7xEwU6z1AKCUTi1VSUVzGvqn3Uo
 aLwvVn8yVt7XBpOWX8TiFuZ4cg9Qett3olpUNdJIuWE2PRueNvSH9BVCjb44UoFHmHwH
 2MKQ==
X-Gm-Message-State: AGi0PuYXxck+hbczajAtmnsWZj1oBZtPfGhwnMxy1BtUf/5fircPs/tp
 H3huq/xju23EBfflCdmG+gB4ngT8V3E=
X-Google-Smtp-Source: APiQypK1GTeUxjyqv52u+hzgqt3Fn4Px2zCazqtLFB34nSgooU19gfpRCUk86qHYHlgWfStQfOnlCQ==
X-Received: by 2002:a05:6830:160c:: with SMTP id
 g12mr523359otr.335.1586975426578; 
 Wed, 15 Apr 2020 11:30:26 -0700 (PDT)
Received: from [192.168.10.3] ([200.57.195.23])
 by smtp.gmail.com with ESMTPSA id m90sm1160401otc.37.2020.04.15.11.30.25
 for <cygwin@cygwin.com>
 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);
 Wed, 15 Apr 2020 11:30:26 -0700 (PDT)
Subject: Re: Can I find where cygwin is installed (for automation purposes)
To: cygwin@cygwin.com
References: <CACac1F9BvE0nqGru8=NxA7pc=6VPF_sokUPS94Wr1NfRQeLN5w@mail.gmail.com>
 <fea3d3d3-3ba0-7b8c-8c5c-c2793a397762@gmail.com>
 <CACac1F8jd0BJrg3kuw-sWkffc9Hn56ZRLgfpFE_CE1p6FL+kvw@mail.gmail.com>
 <08f1afcc-e045-25c5-6b7d-c37ee841b6c2@gmail.com>
 <CACac1F_ptn5Td_x5K2-8m5mqbiRN30NjJkrQWqPFiuQmx6FCnw@mail.gmail.com>
From: =?UTF-8?Q?Ren=c3=a9_Berber?= <rene.berber@gmail.com>
Message-ID: <707d4053-71ab-7368-9b4d-8df25408dde9@gmail.com>
Date: Wed, 15 Apr 2020 13:30:29 -0500
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.19)
 Gecko/20081209 Lightning/0.9 Thunderbird/2.0.0.19 Mnenhy/0.7.6.0
MIME-Version: 1.0
In-Reply-To: <CACac1F_ptn5Td_x5K2-8m5mqbiRN30NjJkrQWqPFiuQmx6FCnw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00, DKIM_SIGNED,
 DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,
 SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2
X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on
 server2.sourceware.org
X-BeenThere: cygwin@cygwin.com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <http://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request@cygwin.com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin@cygwin.com>
List-Help: <mailto:cygwin-request@cygwin.com?subject=help>
List-Subscribe: <http://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request@cygwin.com?subject=subscribe>
X-List-Received-Date: Wed, 15 Apr 2020 18:30:30 -0000

On 4/15/2020 1:10 PM, Paul Moore via Cygwin wrote:

[snip]
> Thanks. Can you explain what the \?? prefix on the Installations
> values is about? I'm nervous that there's something going on there
> that means that just ignoring the first 3 characters isn't
> sufficient... ;-)

https://docs.microsoft.com/en-us/dotnet/standard/io/file-path-formats

Look for "DOS device paths"
-- 
R.B.