From: Eli Zaretskii <eliz@gnu.org>
To: emacs-devel@gnu.org
Subject: sleep-for documentation and how to pause reliably
Date: Fri, 15 Feb 2013 11:22:00 +0200 [thread overview]
Message-ID: <83mwv6szif.fsf@gnu.org> (raw)
Am I missing something, or is our current docs of sleep-for misleading?
The doc string says:
(sleep-for SECONDS &optional MILLISECONDS)
Pause, without updating display, for SECONDS seconds.
The only way I can interpret this is that sleep-for _always_ pauses
for that number of seconds.
The ELisp manual goes even further:
-- Function: sleep-for seconds &optional millisec
This function simply pauses for SECONDS seconds without updating
the display. It pays no attention to available input. It returns
`nil'. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[...]
Use `sleep-for' when you wish to guarantee a delay.
^^^^^^^^^^^^^^^^^
"Guarantee a delay". No "buts".
However, in fact, sleep-for will return as soon as any input from any
subprocess arrives. E.g., try this in *scratch*:
(progn (setq proc (start-process-shell-command "ls" nil "ls"))
(sleep-for 20)
(message "hi"))
You will see no delay at all before the message is displayed.
Am I missing something? If not, apart of fixing the docs, _is_ there
any way to wait reliably when async subprocesses are running and
producing output?
next reply other threads:[~2013-02-15 9:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-15 9:22 Eli Zaretskii [this message]
2013-02-15 10:19 ` sleep-for documentation and how to pause reliably Thierry Volpiatto
2013-02-15 13:18 ` Eli Zaretskii
2013-02-15 20:36 ` Thierry Volpiatto
2013-02-16 8:40 ` Eli Zaretskii
2013-02-17 11:58 ` Xue Fuqiao
2013-02-17 16:26 ` Eli Zaretskii
2013-02-17 23:41 ` Xue Fuqiao
2013-02-15 16:11 ` Stefan Monnier
2013-02-15 18:24 ` Eli Zaretskii
2013-02-15 20:36 ` Stefan Monnier
2013-03-02 20:48 ` Johan Bockgård
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