lispdoc - results for force-output

(force-output &optional (stream *standard-output*))
Undocumented
Example:
(defun prompt-read (prompt)
  (format *query-io* "~a: " prompt)
  (force-output *query-io*)
  (read-line *query-io*))
Mentioned in:
CLtL2 - 22.3.1. Output to Character Streams
HyperSpec - Function FINISH-OUTPUT, FORCE-OUTPUT, CLEAR-OUTPUT
PCL - improving the user interaction
Successful Lisp - chapter19
(trivial-gray-streams:stream-force-output stream)
Function: Attempts to force any buffered output to be sent. Implements FORCE-OUTPUT. The default method does nothing.