DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 51FGTlSc2094409
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4F2623858C42
Message-ID: <54763b8c-ae4f-4616-85e4-f93edd9513d5@hamachi.org>
Date: Sat, 15 Feb 2025 08:28:30 -0800
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [developer] Re: SEEK_DATA should fail at EOF
To: developer@lists.illumos.org, Cedric Blancher <cedric.blancher@gmail.com>,
        cygwin@cygwin.com
References: <614771e9-592c-6154-d56d-13842b6fc6ac@t-online.de>
 <5ccdf4be-4e4b-1846-9fd6-cba29c9dbb11@t-online.de>
 <CALXu0UcYLMhnOtQ2emvoH7=EpjuxcZmqf8+B8xY8YU8dxk7_Og@mail.gmail.com>
Content-Language: en-US
In-Reply-To: <CALXu0UcYLMhnOtQ2emvoH7=EpjuxcZmqf8+B8xY8YU8dxk7_Og@mail.gmail.com>
Precedence: list
From: Bill Sommerfeld via Cygwin <cygwin@cygwin.com>
Reply-To: Bill Sommerfeld <sommerfeld@hamachi.org>
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Errors-To: cygwin-bounces~archive-cygwin=delorie.com@cygwin.com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie.com@cygwin.com>

On 2/14/25 23:42, Cedric Blancher wrote:
> cc: illumos-dev@ list. How does Solaris or Illumos behave? SUN/Solaris
> invented SEEK_DATA/SEEK_HOLE, so this should be - aside from looking
> at the OpenGroup/POSIX specs - the reference implementation.

Thanks for asking.

On Illumos, SEEK_DATA fails with ENXIO at EOF, and more generally fails 
with ENXIO if there are no non-hole regions in the file after the passed 
offset -- a file may end in a hole, so you may also get ENXIO for 
offsets less than the file's length.

The lseek manpage says:

...
ERRORS
        The lseek() function will fail if:
...
        ENXIO
            For SEEK_DATA, there are no more data regions past the
            supplied offset.  For SEEK_HOLE, there are no more holes
            past the supplied offset.

						- Bill


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple