From: Peter Stephenson <p.stephenson@samsung.com>
To: <zsh-workers@zsh.org>
Subject: Re: zsh 5.6 regression: a pipe sometimes yields a TTOU signal
Date: Thu, 6 Sep 2018 13:55:42 +0100 [thread overview]
Message-ID: <20180906125543eucas1p1368a619a1ff04988622b864e38f9c4f6~R0NDo76GJ0949909499eucas1p13@eucas1p1.samsung.com> (raw)
In-Reply-To: <20180906123657.GD29649@cventin.lip.ens-lyon.fr>
On Thu, 6 Sep 2018 14:36:57 +0200
Vincent Lefevre <vincent@vinc17.net> wrote:
> Perhaps I misunderstood. The solution is not something like
>
> echo | { ( sww ) | less }
>
> but
>
> echo | ( sww | less )
Yes, that's what I meant.
In the first example there are still Rimmerworld(*) pipelines:
"echo | ... " and "(sww) | less" are two different pipelines
being managed in the same shell. This is the root of the
problem, with various ramifications.
In the second case, "echo | ..." is in one shell, and then
"sww | less" is managed entirely by a forked copy of the shell,
so the basic issue doesn't occur.
In principle (and depending a bit on options, open FDs, etc.)
the second one should be just as efficient --- the fork occurs
earlier but the "less" is run by an exec of the forked shell.
pws
(*) https://www.youtube.com/watch?v=py3u3P9OpBE
OK, the actual relevance *is* a bit obscure.
next prev parent reply other threads:[~2018-09-06 12:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20180905091407epcas1p1ff78da39bfd4f3e4201f467683288a7b@epcas1p1.samsung.com>
2018-09-05 9:03 ` Vincent Lefevre
2018-09-05 10:03 ` Peter Stephenson
2018-09-05 10:55 ` Vincent Lefevre
2018-09-05 12:22 ` Vincent Lefevre
2018-09-05 13:17 ` Vincent Lefevre
2018-09-05 13:37 ` Vincent Lefevre
2018-09-05 14:40 ` Peter Stephenson
2018-09-06 11:40 ` Vincent Lefevre
2018-09-06 12:26 ` Vincent Lefevre
2018-09-06 12:36 ` Vincent Lefevre
2018-09-06 12:55 ` Peter Stephenson [this message]
2018-09-05 12:53 ` Peter Stephenson
2018-09-05 13:21 ` Peter Stephenson
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