Function: follow-pre-redisplay-function
follow-pre-redisplay-function is a byte-compiled function defined in
follow.el.gz.
Signature
(follow-pre-redisplay-function WINS)
Source Code
;; Defined in /usr/src/emacs/lisp/follow.el.gz
;; This function is added to `pre-redisplay-function' and is thus called
;; before each redisplay operation. It supersedes (2018-09) the
;; former use of the post command hook, and now does the right thing
;; when a program calls `redisplay' or `sit-for'.
(defun follow-pre-redisplay-function (wins)
(if (or (eq wins t)
(null wins)
(and (listp wins)
(memq (selected-window) wins)))
(follow-post-command-hook)))