Variable: isearch-message-function
isearch-message-function is a variable defined in isearch.el.gz.
Value
nil
Documentation
Function to call to display the search prompt.
If nil, use function isearch-message(var)/isearch-message(fun).
Source Code
;; Defined in /usr/src/emacs/lisp/isearch.el.gz
(defvar isearch-message-function nil
"Function to call to display the search prompt.
If nil, use function `isearch-message'.")