Re: Forwarding stdout/stderr of a child process in batch mode

[Paul Pogonyshev]

Thank you, this seems to work (haven't tried separating stderr from
stdout yet). Is there a normal way to wait for asynchronous process to
terminate? Currently I have managed to make it work by throwing from
sentinel, but this feels a bit hackish, maybe there is something
better?

Currently I have something like this:

    (let ((process (make-process ... :sentinel (lambda (_process
_event) (throw 'done nil)))))
      (catch 'done
        (while (process-live-p process)
          (accept-process-output nil 60)))
      ...

Paul

On Sun, 6 Dec 2020 at 14:37, Zhu Zihao <all_but_last@163.com> wrote:
>
>
> IMO, in batch mode, `message` writes to stderr, `princ` writes to
> stdout. You can install a filter for childprocess, and run functions I
> mentioned above to forward these outputs.
>
>
> Paul Pogonyshev writes:
>
> > Hi,
> >
> > I'm using Emacs in batch mode. I need to invoke a child process that
> > is a longish operation (a few minutes). During this time, it writes to
> > its stdout, so user will see that it is working and what exactly is
> > being done. However, if I invoke it from Emacs (e.g. using
> > `call-process') I see no way of forwarding this output to the "real"
> > stdout. So, for a user this looks like the process (or batch Emacs on
> > top of it) is hung.
> >
> > Am I missing a way to forward output?
> >
> > Paul
>
>
> --
> Retrieve my PGP public key: https://meta.sr.ht/~citreu.pgp
>
> Zihao