default directory.
@defun read-file-name prompt &optional directory default require-match initial predicate
-This function reads a file name in the minibuffer, prompting with
-@var{prompt} and providing completion.
+This function reads a file name, prompting with @var{prompt} and
+providing completion.
+
+As an exception, this function reads a file name using a graphical
+file dialog instead of the minibuffer, if (i) it is invoked via a
+mouse command, and (ii) the selected frame is on a graphical display
+supporting such dialogs, and (iii) the variable @code{use-dialog-box}
+is non-@code{nil} (@pxref{Dialog Boxes,, Dialog Boxes, emacs, The GNU
+Emacs Manual}), and (iv) the @var{directory} argument, described
+below, does not specify a remote file (@pxref{Remote Files,, Remote
+Files, emacs, The GNU Emacs Manual}). The exact behavior when using a
+graphical file dialog is platform-dependent. Here, we simply document
+the behavior when using the minibuffer.
The optional argument @var{require-match} has the same meaning as in
@code{completing-read}. @xref{Minibuffer Completion}.
@var{directory} is also inserted in the minibuffer as initial input.
It defaults to the current buffer's value of @code{default-directory}.
-@c Emacs 19 feature
If you specify @var{initial}, that is an initial file name to insert
in the buffer (after @var{directory}, if that is inserted). In this
case, point goes at the beginning of @var{initial}. The default for