1 files changed, 14 insertions, 10 deletions

diff --git a/lisp/ediff-util.el b/lisp/ediff-util.el
index e87cd821e32..6f864639c7a 100644
--- a/lisp/ediff-util.el
+++ b/lisp/ediff-util.el
@@ -2899,33 +2899,37 @@ Hit \\[ediff-recenter] to reset the windows afterward."
     f)) 
   
 ;; If PREFIX is given, then it is used as a prefix for the temp file
-;; name. Otherwise, `ediff_' is used. If FILE is given, use this
+;; name. Otherwise, `ediff' is used. If FILE is given, use this
 ;; file and don't create a new one.
-;; On MS-DOS, make sure the prefix isn't longer than 7 characters, or
-;; else `make-temp-name' isn't guaranteed to return a unique filename.
+;; On MS-DOS, make sure the prefix isn't too long, or else
+;; `make-temp-name' isn't guaranteed to return a unique filename.
 ;; Also, save buffer from START to END in the file.
 ;; START defaults to (point-min), END to (point-max)
 (defun ediff-make-temp-file (buff &optional prefix given-file start end)
-  (let ((p (or prefix "ediff"))
-        f)
-    (if (and (eq system-type 'ms-dos) (> (length p) 7))
-        (setq p (substring p 0 7)))
+  (let* ((p (ediff-convert-standard-filename (or prefix "ediff")))
+         (short-p p)
+         f short-f)
+    (if (and (fboundp 'msdos-long-file-names)
+             (not (msdos-long-file-names))
+             (> (length p) 2))
+        (setq short-p (substring p 0 2)))
 
     (setq f (concat ediff-temp-file-prefix p)
+          short-f (concat ediff-temp-file-prefix short-p)
           f (cond (given-file)
                   ((find-file-name-handler f 'find-file-noselect)
                    ;; to thwart file handlers in write-region, e.g., if file
                    ;; name ends with .Z or .gz
                    ;; This is needed so that patches produced by ediff will
                    ;; have more meaningful names
-                   (make-temp-name f))
+                   (make-temp-name short-f))
                   ;; Prefix is most often the same as the file name for the
                   ;; variant. Here we are trying to use the original file name
                   ;; but in the temp directory.
                   ((and prefix (not (file-exists-p f))) f)
                   ;; If a file with the orig name exists, add some random stuff
                   ;; to it.
-                  (t (make-temp-name f))))
+                  (t (make-temp-name short-f))))
     
     ;; create the file
     (ediff-with-current-buffer buff
@@ -2935,7 +2939,7 @@ Hit \\[ediff-recenter] to reset the windows afterward."
                     nil          ; don't append---erase
                     'no-message) 
       (set-file-modes f ediff-temp-file-mode)
-      (ediff-convert-standard-filename (expand-file-name f)))))
+      (expand-file-name f))))
 
 ;; Quote metacharacters (using \) when executing diff in Unix, but not in
 ;; EMX OS/2