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Re: bin/57894: sh(1): PID obtained with jobs -p is always 0 on NetBSD 10.0 RC
The following reply was made to PR bin/57894; it has been noted by GNATS.
From: Koichi Nakashima <koichi%nksm.name@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc:
Subject: Re: bin/57894: sh(1): PID obtained with jobs -p is always 0 on NetBSD
10.0 RC
Date: Wed, 31 Jan 2024 08:18:08 +0900
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Thanks for the fixing and the detailed explanation.
My concern was backward compatibility.
I probably won't use the jobs command with
non-interactive shells (unless it is absolutely necessary).
2024=E5=B9=B41=E6=9C=8831=E6=97=A5(=E6=B0=B4) 4:05 Robert Elz <kre@munnari.=
oz.au>:
> The following reply was made to PR bin/57894; it has been noted by GNATS.
>
> From: Robert Elz <kre%munnari.OZ.AU@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc:
> Subject: Re: bin/57894: sh(1): PID obtained with jobs -p is always 0 on
> NetBSD 10.0 RC
> Date: Wed, 31 Jan 2024 02:00:44 +0700
>
> Date: Tue, 30 Jan 2024 13:35:00 +0000 (UTC)
> From: koichi%nksm.name@localhost
> Message-ID: <20240130133500.967921A923A%mollari.NetBSD.org@localhost>
>
> | >Synopsis: sh(1): PID obtained with jobs -p is always 0 on
> NetBSD 10.0 RC
>
> | $ sh -c 'sleep 3 & echo $!; jobs -l; jobs -p'
> | 7975
> | [1] + 7975 Running sleep 3 &
> | 0
>
> This wasn't intended, and I am about to commit a fix, but at
> least according to POSIX, that isn't required to work.
>
> -p Display only the process IDs for the process group leaders of
> job-control
> background jobs and the process IDs associated with non-job-contro=
l
> background jobs (if supported).
>
> Non-interactive shells (which is what that is) don't enable job control,
> so that sleep 3 is a non-job-control background job, and we're not
> required
> to support -p for those.
>
> If job control were enabled, as in
>
> sh -c 'set -m; sleep 3 & echo $!; jobs -l; jobs -p'
>
> then it would work (in -10, and HEAD, without the coming fix).
>
> The issue is a fix that was making sure the correct value was
> always output for job-control jobs (there were ways, in more complex
> examples, to get the wrong pid printed). But the non-job-control
> ones just got forgotten. Oops...
>
> For now, in the non-job-control case, sh will just do what it used to do
> (while still doing it the new way for job-controlled background jobs).
>
>
>
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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr">Thanks for the fixing an=
d the detailed explanation.</div><div dir=3D"ltr">My concern was backward c=
ompatibility.</div><div dir=3D"ltr">I probably won't use the jobs comma=
nd with</div><div dir=3D"ltr">non-interactive shells (unless it is absolute=
ly necessary).<br></div><br class=3D"gmail-Apple-interchange-newline"></div=
><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">2024=
=E5=B9=B41=E6=9C=8831=E6=97=A5(=E6=B0=B4) 4:05 Robert Elz <<a href=3D"ma=
ilto:kre%munnari.oz.au@localhost">kre%munnari.oz.au@localhost</a>>:<br></div><blockquote cla=
ss=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid =
rgb(204,204,204);padding-left:1ex">The following reply was made to PR bin/5=
7894; it has been noted by GNATS.<br>
<br>
From: Robert Elz <<a href=3D"mailto:kre%munnari.OZ.AU@localhost"; target=3D"_blank"=
>kre%munnari.OZ.AU@localhost</a>><br>
To: <a href=3D"mailto:gnats-bugs%netbsd.org@localhost"; target=3D"_blank">gnats-bugs@n=
etbsd.org</a><br>
Cc: <br>
Subject: Re: bin/57894: sh(1): PID obtained with jobs -p is always 0 on Net=
BSD 10.0 RC<br>
Date: Wed, 31 Jan 2024 02:00:44 +0700<br>
<br>
=C2=A0 =C2=A0 =C2=A0Date:=C2=A0 =C2=A0 =C2=A0 =C2=A0 Tue, 30 Jan 2024 13:35=
:00 +0000 (UTC)<br>
=C2=A0 =C2=A0 =C2=A0From:=C2=A0 =C2=A0 =C2=A0 =C2=A0 <a href=3D"mailto:koic=
hi%nksm.name@localhost" target=3D"_blank">koichi%nksm.name@localhost</a><br>
=C2=A0 =C2=A0 =C2=A0Message-ID:=C2=A0 <<a href=3D"mailto:20240130133500.=
967921A923A%mollari.NetBSD.org@localhost" target=3D"_blank">20240130133500.967921A923=
A%mollari.NetBSD.org@localhost</a>><br>
<br>
=C2=A0 =C2=A0| >Synopsis:=C2=A0 =C2=A0 =C2=A0 =C2=A0sh(1): PID obtained =
with jobs -p is always 0 on NetBSD 10.0 RC<br>
<br>
=C2=A0 =C2=A0| $ sh -c 'sleep 3 & echo $!; jobs -l; jobs -p'<br=
>
=C2=A0 =C2=A0| 7975<br>
=C2=A0 =C2=A0| [1] + 7975 Running=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
sleep 3 &<br>
=C2=A0 =C2=A0| 0<br>
<br>
=C2=A0This wasn't intended, and I am about to commit a fix, but at<br>
=C2=A0least according to POSIX, that isn't required to work.<br>
<br>
=C2=A0 =C2=A0 -p Display only the process IDs for the process group leaders=
of job-control<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0background jobs and the process IDs associated w=
ith non-job-control<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0background jobs (if supported).<br>
<br>
=C2=A0Non-interactive shells (which is what that is) don't enable job c=
ontrol,<br>
=C2=A0so that sleep 3 is a non-job-control background job, and we're no=
t required<br>
=C2=A0to support -p for those.<br>
<br>
=C2=A0If job control were enabled, as in<br>
<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 sh -c 'set -m; sleep 3 & echo $!; jobs =
-l; jobs -p'<br>
<br>
=C2=A0then it would work (in -10, and HEAD, without the coming fix).<br>
<br>
=C2=A0The issue is a fix that was making sure the correct value was<br>
=C2=A0always output for job-control jobs (there were ways, in more complex<=
br>
=C2=A0examples, to get the wrong pid printed).=C2=A0 =C2=A0But the non-job-=
control<br>
=C2=A0ones just got forgotten.=C2=A0 =C2=A0Oops...<br>
<br>
=C2=A0For now, in the non-job-control case, sh will just do what it used to=
do<br>
=C2=A0(while still doing it the new way for job-controlled background jobs)=
.<br>
<br>
<br>
</blockquote></div></div>
--0000000000006d318e061031faed--
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