Sleep: Difference between revisions

=={{header|Emacs Lisp}}==

<lang lisp>(let ((seconds (read-number "Time in seconds: ")))

(message "Sleeping ...")

(sleep-for seconds)

(message "Awake!"))</lang>

The time can be a decimal like 1.5 though the actual resolution of <code>sleep-for</code> depends on the operating system. The similar <code>sit-for</code> stops sleeping if there's pending keyboard input.

<code>read-number</code> is new in Emacs 22 and XEmacs 21. In earlier versions similar can be had with

<lang lisp>(string-to-number (read-string "Time in seconds: "))</lang>

This returns 0 on a non-number whereas <code>read-number</code> re-prompts (except in Emacs 24.3 where a bug caused <code>read-number</code> to return 0 :-( ).