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Date: Mon, 4 Apr 2016 17:16:44 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Unreliable flock
Message-ID: <20160404151644.GB29337@calimero.vinschen.de>
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References: <175808986 DOT 20160403002257 AT yandex DOT ru>
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On Apr  3 00:22, Andrey Repin wrote:
> Greetings, All!
>=20
> The script (let's call it test.sh):
>=20
> #!/bin/dash -x
> _lock=3D"./console-session.lock"
> {
>   flock -n 9 || {
>       echo "The $(cat "$_lock") command is running already."
>       exit 3
>     } >&2
>=20
>   printf "$1" >&9
>=20
>   trap 'rm "$_lock";' EXIT HUP INT ABRT TERM
>=20
>   sleep 20
>=20
> } 9>> "$_lock"
>=20
> Very simple in essence.
> The one-liner:
>=20
> { flock -n 9 && sleep 10 || echo Fail;} 9>> ./console-session.lock
>=20
> Also extremely simple.
>=20
> Open two terminals. mintty or native, bash or dash, doesn't matter.
> chdir to the directory with the script.
>=20
> Start script in one terminal. ./test.sh
> Start oneliner in another terminal. Fail. How predictable!

I don't know what I'm doing wrong, but this WJFFM with Cygwin 2.4.1
as well as 2.5.0.  Additionally I tried to put the oneliner into a
script but it still WFM.

Apart from that, did you notice the flock restrictions outlined in
https://cygwin.com/cygwin-api/std-notes.html ?


Corinna

--=20
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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