Variable: eldoc-message-function
eldoc-message-function is a variable defined in eldoc.el.gz.
Value
eldoc-minibuffer-message
Documentation
The function used by eldoc--message to display messages.
It should receive the same arguments as message.
Source Code
;; Defined in /usr/src/emacs/lisp/emacs-lisp/eldoc.el.gz
(defvar eldoc-message-function #'eldoc-minibuffer-message
"The function used by `eldoc--message' to display messages.
It should receive the same arguments as `message'.")