Re: wait inside subshell waits for sibling

[Chet Ramey]

On 10/24/22 4:52 AM, Emanuele Torre wrote:
> On 24/10/2022, Robert Elz <kre@munnari.oz.au> wrote:

> > There's no reason that wait (the command) cannot check for candidate
> > jobs which are still running, and wait for any of those, and then
> > return as soon as there are none left.   That the shell happens to
> > have forked other processes for its own reasons should make no
> > difference at all.
>
> Process substitutions are considered background jobs, and the wait
> builtin waits for them.

They're not jobs: they don't go in the jobs list, `jobs' doesn't report
on them, and fg/bg don't affect them. They're asynchronous processes
that happen to set $! (which may have been a mistake, but too late now).

`wait' can wait for them because they set $!, but as documented `wait'
without arguments only waits for the last one, and only if its pid is
the same as $!.

In POSIX terms, they are "known to the current shell execution
environment."

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/