> On Mon, 23 Mar 2020 20:43:56 +0100 Uwe Brauer <oub@mat.ucm.es> wrote:

   > You're calling insert-buffer-substring with point-min and point-max of
   > the buffer you've just created, so they're both 1.  Try this:

   > (defun my-copy-to-buffer (buffer)
   >   "Copy the contents of the current buffer to  BUFFER."
   >   (interactive "BCopy to buffer: ")
   >   (let ((start (point-min))
   > 	(end (point-max)))
   >     (copy-to-buffer buffer start end)))

Thanks I tried this 


(defun my-copy-to-buffer (buffer)
  "Copy to specified BUFFER the whole buffer."
  (interactive "BCopy to buffer: \n")
  (let ((oldbuf (current-buffer))
        (start (point-min))
        (end (point-max)))
    
    (with-current-buffer (get-buffer-create buffer)
      (barf-if-buffer-read-only)
      (save-excursion
	(insert-buffer-substring oldbuf (point-min) (point-max))))))

And it did not work,

Your code works though.


I will never understand let


Uwe