From: michael@kjorling.se (Michael Kjörling)
Subject: [TUHS] fstat(2) on pipes?
Date: Mon, 15 Aug 2016 16:56:45 +0000 [thread overview]
Message-ID: <20160815165645.GE655@yeono.kjorling.se> (raw)
In-Reply-To: <1471274085.1099635.695741217.6472725F@webmail.messagingengine.com>
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On 15 Aug 2016 11:14 -0400, from random832 at fastmail.com (Random832):
> On Mon, Aug 15, 2016, at 10:04, Noel Chiappa wrote:
>> But back to the original topic, it sounds like there's a huge amount
>> of variance in the semantics of doing fstat() on a pipe. V6 doesn't
>> special-case it in any way, but it sounds as if other systems do.
>
> I expect that the single important thing, the only thing that most
> applications will rely on, is it returning successfully and indicating
> that the file type is fifo.
On Linux/glibc, based on the fstat(2) man page, it looks like the size
field is undefined for a FIFO:
> The st_size field gives the size of the file (if it is a regular
> file or a symbolic link) in bytes. The size of a symbolic link is
> the length of the pathname it contains, without a terminating null
> byte.
The mode field is used to hold the type of file:
> The following POSIX macros are defined to check the file type using
> the st_mode field:
>
> ...
> S_ISFIFO(m) FIFO (named pipe)?
> ...
>
> The following flags are defined for the st_mode field:
> ...
> S_IFIFO 0010000 FIFO
> ...
The above from Debian Wheezy.
--
Michael Kjörling • https://michael.kjorling.se • michael at kjorling.se
“People who think they know everything really annoy
those of us who know we don’t.” (Bjarne Stroustrup)
next prev parent reply other threads:[~2016-08-15 16:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-15 14:04 Noel Chiappa
2016-08-15 15:14 ` Random832
2016-08-15 16:56 ` Michael Kjörling [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-08-15 17:47 Norman Wilson
2016-08-15 0:27 Noel Chiappa
2016-08-15 0:59 ` Warren Toomey
2016-08-15 0:11 Warren Toomey
2016-08-15 0:41 ` Dave Horsfall
2016-08-15 0:54 ` Warren Toomey
2016-08-15 17:53 ` Clem Cole
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