Re: "builtin jobs" does not output to stdout.

[Koichi Murase]

2023年2月15日(水) 1:20 Chet Ramey <chet.ramey@case.edu>:
>
> On 2/13/23 6:43 AM, Koichi Murase wrote:
>
> > I guess just the support for ksh's ${ list; } [1] would make
> > everything simple and clear. One can simply call ${ jobs; }, ${ trap
> > -p; }, etc. without thinking about subshells.
> >
> > [1] https://lists.gnu.org/archive/html/help-bash/2020-05/msg00077.html
>
> The text about syntatic sugar still applies.
> > I haven't checked what POSIX says about the jobs in subshells,
>
> POSIX requires that the shell execution environment include what is
> essentially the jobs list;

Thank you for the information. This is what I wanted to find. Thank
you. (At that time, I just quickly searched for the job list, but I
couldn't find it. Also the definition of "a job" didn't seem to be
given in the standard, but I now found "Background Jobs" in XBD)

> https://www.austingroupbugs.net/view.php?id=1254
>
> discusses this extensively. However,
>
> "The jobs utility does not work as expected when it is operating in its own
> utility execution environment because that environment has no applicable
> jobs to manipulate."
>
>
> > but at
> > least Bash maintains a separate "job list" of a subshell (which is
> > accessible from the built-in command `jobs') regardless of whether the
> > "job control" is turned on or not.
>
> POSIX requires this:
>
> "The jobs utility is not dependent on the job control option, as are the
> seemingly related bg and fg utilities because jobs is useful for examining
> background jobs, regardless of the condition of job control."

Thank you for all the information.

--
Koichi