From: paul.winalski@gmail.com (Paul Winalski)
Subject: [TUHS] EOF on pipes?
Date: Sun, 25 Feb 2018 11:29:50 -0500 [thread overview]
Message-ID: <CABH=_VRvecPU8CkfD8CYQM4tKGcF90UdN+vDkFyYif790aUjfQ@mail.gmail.com> (raw)
In-Reply-To: <1519519996.29346.for-standards-violators@oclsc.org>
On 2/24/18, Norman Wilson <norman at oclsc.org> wrote:
> Many years ago (when the dinosaurs were using V6), I had a crazy idea[*]
> that a write(fd, 0, NULL) would somehow signal EOF to the reader i.e. a
> subsequent read would wait for further data instead of ENOTOBACCO.
>
> Did any *nix ever implement that? I have no idea how it would be done.
>
The pipe device driver that I wrote for VMS implemented EOF.
Mailboxes (the moral equivalent of pipes in VMS) had a WRITE_EOF I/O
command in addition to the usual WRITE. This placed a special record
in the mailbox's data stream that caused the driver to return
end-of-file when a READ was done instead of simply waiting for further
data. My pipe driver had to be fully compatible with mailboxes, so it
also had WRITE_EOF.
-Paul W.
next prev parent reply other threads:[~2018-02-25 16:29 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-25 0:53 Norman Wilson
2018-02-25 16:29 ` Paul Winalski [this message]
2018-02-25 22:25 ` Lyndon Nerenberg
2018-02-25 23:18 ` Bakul Shah
2018-02-26 2:39 ` Grant Taylor
-- strict thread matches above, loose matches on Subject: below --
2018-02-27 5:04 Rudi Blom
2018-02-27 5:48 ` Dave Horsfall
2018-02-25 13:07 Doug McIlroy
2018-02-25 13:16 ` George Michaelson
2018-02-25 13:56 ` arnold
2018-02-24 21:33 Dave Horsfall
2018-02-24 23:13 ` Ron Natalie
2018-02-24 23:42 ` Bakul Shah
2018-02-24 23:46 ` Nelson H. F. Beebe
2018-02-24 23:46 ` Jon Steinhart
2018-02-26 16:03 ` Rudi Blom
2018-02-26 16:58 ` Ian Zimmerman
2018-02-26 17:19 ` Larry McVoy
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