clear-input
&optional input-stream ⇒ nil
input-stream—an input stream designator. The default is standard input.
Clears any available input from input-stream.
If clear-input does not make sense for input-stream, then clear-input does nothing.
;; The exact I/O behavior of this example might vary from implementation ;; to implementation depending on the kind of interactive buffering that ;; occurs. (The call to SLEEP here is intended to help even out the ;; differences in implementations which do not do line-at-a-time buffering.) (defun read-sleepily (&optional (clear-p nil) (zzz 0)) (list (progn (print '>) (read)) ;; Note that input typed within the first ZZZ seconds ;; will be discarded. (progn (print '>) (if zzz (sleep zzz)) (print '>>) (if clear-p (clear-input)) (read)))) (read-sleepily)|>
> |>>10
<<||>
>|>
>> |>>20
<<| ⇒ (10 20) (read-sleepily t)|>
> |>>10
<<||>
>|>
>> |>>20
<<| ⇒ (10 20) (read-sleepily t 10)|>
> |>>10
<<||>
> |>>20
<<| ; Some implementations won't echo typeahead here.|>
>> |>>30
<<| ⇒ (10 30)
The input-stream is modified.
*standard-input*
Should signal an error of type type-error if input-stream is not a stream designator.
clear-output