1 files changed, 5 insertions, 3 deletions

diff --git a/lisp/diff.el b/lisp/diff.el
index ee49482cfe8..06387062feb 100644
--- a/lisp/diff.el
+++ b/lisp/diff.el
@@ -190,11 +190,12 @@ is nil, REGEXP matches only half a hunk.")
                 (cons msg code))))))
 
 ;;;###autoload
-(defun diff (old new &optional switches)
+(defun diff (old new &optional switches no-async)
   "Find and display the differences between OLD and NEW files.
 Interactively the current buffer's file name is the default for NEW
 and a backup file for NEW is the default for OLD.
-With prefix arg, prompt for diff switches."
+With prefix arg, prompt for diff switches.
+If NO-ASYNC is non-nil, call diff syncrhonously."
   (interactive
    (nconc
     (let (oldf newf)
@@ -249,7 +250,8 @@ With prefix arg, prompt for diff switches."
           (setq buf
                 (compile-internal command
                                   "No more differences" "Diff"
-                                  'diff-parse-differences))
+                                  'diff-parse-differences
+                                  nil nil nil nil nil nil no-async))
           (set-buffer buf)
           (set (make-local-variable 'diff-old-file) old)
           (set (make-local-variable 'diff-new-file) new)