From: Bart Schaefer <schaefer@brasslantern.com>
To: zsh-workers@zsh.org
Subject: Re: Can periodic hook stop rescheduling?
Date: Tue, 13 Sep 2016 09:18:22 -0700 [thread overview]
Message-ID: <160913091822.ZM29020@torch.brasslantern.com> (raw)
In-Reply-To: <20160913142003.480cfd9c@pwslap01u.europe.root.pri>
[>workers]
On Sep 13, 2:20pm, Peter Stephenson wrote:
} Subject: Re: Can periodic hook stop rescheduling?
}
} On Tue, 13 Sep 2016 10:49:35 +0200
} Sebastian Gniazdowski <sgniazdowski@gmail.com> wrote:
} > I'm using sched to call a function. The problem is, it sometimes
} > doesn't reschedule.
}
} The function that's being called is certainly not immune from getting
} ^C, and that can certainly stop "sched +2" in its tracks just like any
} other command. The only general fix for this would be blocking SIGINT
} sufficiently early that ^C doesn't hit this and restoring it later ---
} but given sched +2 is the first line of the script anyway that doesn't
} look promising.
I suspect that what's happening is that the interrupt arrives during
the user input loop such that errflag is already set before the sched
function even begins running; and it therefore stops immediately on
entry without executing any actual commands.
Unfortunately it's a race condition so it's difficult to test/prove
this hypothesis. However, there's pretty minimal testing of errflag
in preprompt() and none at all in cacl_timeout() so it might suffice
to check errflag and if set then defer the sched processing until the
next opportunity. There would still be a race possible, but the window
would be much smaller.
The other (not mutually exclusive) option would be to make recurring
schedules part of the "sched" builtin itself, so that if a recurrent
event were interrupted it would nevertheless be rescheduled for the
next interval.
Neither of these is going to help Sebastian with 5.2-and-earlier.
next parent reply other threads:[~2016-09-13 16:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20160913085130eucas1p19723ac09c11d596542360173e4a4b308@eucas1p1.samsung.com>
[not found] ` <CAKc7PVDkrKD_2VyvO_2JigwfvU1m=3QwO4Vac=HgHZNbOOU7pA@mail.gmail.com>
[not found] ` <20160913142003.480cfd9c@pwslap01u.europe.root.pri>
2016-09-13 16:18 ` Bart Schaefer [this message]
2016-09-14 19:04 ` Peter Stephenson
2016-09-15 4:51 ` Bart Schaefer
2016-09-15 10:18 ` Sebastian Gniazdowski
2016-09-15 22:19 ` Bart Schaefer
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