W3C home > Mailing lists > Public > public-ldp-wg@w3.org > January 2013

Re: LDPRs, LDPCs and the mysterious X

From: Mo McRoberts <Mo.McRoberts@bbc.co.uk>
Date: Fri, 25 Jan 2013 12:48:14 +0000
To: Andy Seaborne <andy.seaborne@epimorphics.com>
CC: "<public-ldp-wg@w3.org>" <public-ldp-wg@w3.org>
Message-ID: <923F0B3E-FC11-45B2-B68F-0A438F319FC1@bbc.co.uk>
<pointless-pedantism>

To be pedantic, at the filesystem level directories _are_ files, as well as much of the plumbing above it. To prevent accidental oddness, SOME systems enforce a separate set of APIs for reading directories, and the Single UNIX Specification makes specific allowances for this:

[EISDIR]
[XSI]  The fildes argument refers to a directory **and the implementation does not allow** the directory to be read using read() or pread(). The readdir() function should be used instead.

(emphasis mine)

On many Unix-like systems, you can 'cat' a directory just fine, though what you'll get out of it will be just a set of binary dentries, so it probably won't get you too far.

</pointless-pedantism>

On Fri 2013-Jan-25, at 12:40, Andy Seaborne <andy.seaborne@epimorphics.com>
 wrote:

>
>
> On 25/01/13 11:33, Henry Story wrote:
>> everything including directories are files.
>
> Not really:
>
> cat / ==> "cat: /: Is a directory"
> echo $? ==> 1
>
> man 2 read:
> EISDIR
>    fd refers to a directory.
>
>       Andy
>

--
Mo McRoberts - Technical Lead - The Space
0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E,
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Received on Friday, 25 January 2013 12:48:54 UTC

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