Re: Coproc within coproc supported?

[Tadeus Prastowo]

Hi!

On Wed, Nov 16, 2022 at 3:36 PM Chet Ramey <chet.ramey@case.edu> wrote:
>
> On 11/16/22 2:18 AM, Tadeus Prastowo wrote:
> >
> > The Bash 4.3.48 that comes shipped with Ubuntu 16.04 ...
>
> Wow, that's old.

It is, and so I would like thank you very much for keeping Bash in a
good shape for so many years.  I really appreciate it.  Despite using
Bash since 2005 when I knew the GNU project for the very first time, I
have appreciated its high-level programming capabilities only recently
when I have to orchestrate many third-party programs to work in
unison.  I find that Bash is indeed an efficient language when it
comes to a system-wide process management that must be afforded using
only BusyBox and the Linux kernel.

> > Is it true that the intention of the statement in the man page is that
> > at most one coprocess exists for every concurrently running Bash
> > process where $$ expands to the same PID?
>
> No. Coprocs are process-based.

In that case, why does Bash 4.3.48 when executing the following lines
issues the coproc-exists warning despite the fact that if I understand
it correctly, the (...)-construct creates a new process?

coproc sleep 1
echo $$, $BASHPID, $COPROC_PID >&2
(coproc sleep 1; echo $$, $BASHPID, $COPROC_PID >&2; wait)
wait

Thank you.

-- 
Best regards,
Eus