From: Philipp Stephani <p.stephani2@gmail.com>
To: Michael Albinus <michael.albinus@gmx.de>
Cc: Emacs developers <emacs-devel@gnu.org>
Subject: Re: emacs | Pipeline #8399 has failed for master | ee0e259e
Date: Sun, 17 Jan 2021 14:21:20 +0100 [thread overview]
Message-ID: <CAArVCkTqCKauUK42AJSJ8RFVp6rtEpLvjZN=jDkq34GEMEkLLQ@mail.gmail.com> (raw)
In-Reply-To: <87h7nf4twj.fsf@gmx.de>
Am So., 17. Jan. 2021 um 13:42 Uhr schrieb Michael Albinus
<michael.albinus@gmx.de>:
>
> Philipp Stephani <p.stephani2@gmail.com> writes:
>
> Hi Philipp,
>
> > You're right in that (while (accept-process-output PROC 0)) doesn't
> > result in a busy wait, yes. However, since accept-process-output
> > returns nil in that case, it wouldn't wait at all. But these tests
> > (e.g. process-tests-stderr-filter) are clearly intended to wait for
> > process exit; they even contain assertions that the process has
> > exited.
> > I'm still convinced that (while (accept-process-output PROC)) is the
> > only correct way to wait for PROC to finish (see the "Accepting
> > Output" Info node).
>
> I believe, (while (accept-process-output PROC 0)) is the proper way to
> read pending output from an exited process. That's all.
Yeah, I think you're right. However, if we'd need to wait for the
process anyway, we'd need to evaluate
(while (process-live-p PROC) (accept-process-output))
(while (accept-process-output PROC 0))
and that's more complex and subtler than (while (accept-process-output PROC)).
There's another issue that I haven't had the chance to debug yet: If
you evaluate a form like
(let ((tot-calls 0))
(dotimes (i 100)
(let* ((calls 0)
(a (make-process :name "a"
:command (list "bash" "-c" "echo out &&
echo err >&2")
:stderr (generate-new-buffer "*stderr*")
:sentinel (lambda (_a _b) (cl-incf calls))
:noquery t)))
(while (accept-process-output a))
(cl-incf tot-calls calls)))
tot-calls)
then the result will often be significantly less than 100, and I think
Emacs should guarantee that it will be exactly 100 (i.e. that the
sentinel is guaranteed to be called once accept-process-output returns
nil).
next prev parent reply other threads:[~2021-01-17 13:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5feaf98365b55_3f903d428113941@emba.gnu.org.mail>
2020-12-29 15:50 ` emacs | Pipeline #8399 has failed for master | ee0e259e Michael Albinus
2020-12-29 17:12 ` Robert Pluim
2020-12-29 17:42 ` Michael Albinus
2020-12-29 21:23 ` Michael Albinus
2021-01-04 17:20 ` Robert Pluim
2021-01-04 20:38 ` Philipp Stephani
2021-01-05 7:52 ` Michael Albinus
2021-01-05 13:44 ` Philipp Stephani
2021-01-06 12:15 ` Michael Albinus
2021-01-17 10:37 ` Philipp Stephani
2021-01-17 12:42 ` Michael Albinus
2021-01-17 13:21 ` Philipp Stephani [this message]
2021-01-05 9:42 ` Robert Pluim
2021-01-05 9:55 ` Andreas Schwab
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