Variable: read-file-name-function
read-file-name-function is a variable defined in minibuffer.el.gz.
Value
read-file-name-default
Documentation
The function called by read-file-name to do its work.
It should accept the same arguments as read-file-name.
Probably introduced at or before Emacs version 22.1.
Source Code
;; Defined in /usr/src/emacs/lisp/minibuffer.el.gz
(defvar read-file-name-function #'read-file-name-default
"The function called by `read-file-name' to do its work.
It should accept the same arguments as `read-file-name'.")