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  ANSI Common Lisp   25 Environment   25.2 Dictionary of Environment

25.2.4 sleep Function

Syntax:
sleep seconds    nil

Arguments and Values:
seconds - a non-negative real.

Description:
Causes execution to cease and become dormant for approximately the seconds of real time indicated by seconds, whereupon execution is resumed.

Examples:
 (sleep 1)   NIL 

;; Actually, since SLEEP is permitted to use approximate timing, 
;; this might not always yield true, but it will often enough that
;; we felt it to be a productive example of the intent.
 (let ((then (get-universal-time))
       (now  (progn (sleep 10) (get-universal-time))))
   (>= (- now then) 10))
 true

Side Effects:
Causes processing to pause.

Affected By:
The granularity of the scheduler.

Exceptional Situations:
Should signal an error of type type-error if seconds is not a non-negative real.

Allegro CL Implementation Details:
None.

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