Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: vallor <vallor@cultnix.org>
Newsgroups: comp.unix.shell
Subject: Re: Cleaning up background processes
Date: Wed, 8 May 2024 21:04:58 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 44
Message-ID: <v1gpdq$3me9$1@dont-email.me>
References: <slrnv3fm5e.jrj.naddy@lorvorc.mips.inka.de>
	<20240505214609.114@kylheku.com> <v1ah87$l0a8$1@news.xmission.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Injection-Date: Wed, 08 May 2024 23:04:58 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="b4d3f200feaa5642c33106880b90c11a";
	logging-data="121289"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/2efP8e5U18xgFxaWvET1x"
User-Agent: Pan/0.158 (Avdiivka; cf43eb8; Linux-6.8.9)
Cancel-Lock: sha1:dyem2ZqdkR0h5e/Ykz781cQdqlY=
X-Face: \}2`P"_@pS86<'EM:'b.Ml}8IuMK"pV"?FReF$'c.S%u9<Q#U*4QO)$l81M`{Q/n
 XL'`91kd%N::LG:=*\35JS0prp\VJN^<s"b#bff@fA7]5lJA.jn,x_d%Md$,{.EZ
Bytes: 2851

On Mon, 6 May 2024 12:08:39 -0000 (UTC), gazelle@shell.xmission.com (Kenny
McCormack) wrote in <v1ah87$l0a8$1@news.xmission.com>:

> In article <20240505214609.114@kylheku.com>,
> Kaz Kylheku  <643-408-1753@kylheku.com> wrote:
>>On 2024-05-05, Christian Weisgerber <naddy@mips.inka.de> wrote:
>>> Is there a standard POSIX shell idiom to clean up background
>>> processes?
>>>
>>> You have a shell script that starts some background process with &.
>>> Now you want to make sure that the background process terminates when
>>> the shell script terminates.  In particular, when it terminates due to
>>> special circumstances.
>>
>>Maybe have an EXIT trap which calls wait?
> 
> The fundamental underlying problem here is that the EXIT trap is only
> called on a "normal" exit.  In particular, it does not get called under
> (at least) the following circumstances:
> 
>     1) User hits ^C causing the script to abort.

I'm sorry, but I've waited and nobody said anything, so
I have to ask:  Why couldn't you trap "kill -1 0" INT?

>     2) Script exits via an "exec" statement.

This is true, and I can't see any way around that.

> As I read it, that's what this thread is actually about.
> 
> This is a problem I've often grappled with and I'm convinced that there
> is no universal solution.
> 
> Having said that, I think we are all making our own assumptions about
> what the actual, underlying problem is.  Given that OP is not a newbie,
> it would help a lot if he would clarify what exact situation he is
> dealing with, rather than have us all guess (which is SOP when the
> poster *is* a newbie).

Wish they would clarify what they meant...

-- 
-v