Re: possible to use a function that uses a coproc in a pipeline?

[Chet Ramey]

On 3/31/23 5:47 PM, Britton Kerin wrote:
> Overview:
>
> I've been playing around more with coproc and I ran into an issue
> trying to use a function that uses a server coproc in a pipeline.  It
> doesn't work and I can't see how to make it work without
> pipe ends available in subshells.  I wonder if I'm missing some
> obvious way or if it might be possible to add an option to coproc to
> not close the pipe ends?

Bash is pretty careful to close pipe file descriptors on exec, since a
stray open one can lead to hangs and deadlocks.

You can use the `fdflags' loadable builtin together with redirection to
copy whichever file descriptor you want and manipulate it. So if you
want to use a copy of ${sqliteServer[1]}, you use

exec {fdcopy}<&${sqliteServer[1]}
fdflags -s -cloexec ${fdcopy}

and then use ${fdcopy}.

You'll just have to keep the file descriptors straight manually.

--
``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/