Re: questions about coproc

[Grisha Levit]

On Thu, Mar 9, 2023, 13:48 Britton Kerin <britton.kerin@gmail.com> wrote:

> 1.  no obvious way to propagate e.g. the die argument in the above
> back to the controlling terminal.  Is there some easy way to do this
> that I missed?


Maybe you mean something else by "propagate" but:
* stderr is inherited so goes to the terminal unless you've redirected it
when creating the coproc
* the coproc's termination can be detected by the <name>_PID variable
becoming unset (or `kill -0', etc)
* the coproc's exit status can be retrieved with `wait'

$ coproc c { read; echo err >&2; exit 5; }
[1] 16181
$ declare -p c_PID
declare -- c_PID="16181"
$ echo >&${c[1]}
err
[1]+ Exit 5 coproc c { read; echo err 1>&2; exit 5; }
$ declare -p c_PID
bash: declare: c_PID: not found
$ wait 16181; echo $?
5

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