How can I use fuction "append-to-buffer"?

How can I use fuction "append-to-buffer"?

[Wu XiaoGuang]

Hi,all:
  I am reading Emacs Lisp Intro.
  There is one fuction:

(defun append-to-buffer (buffer start end)
       "Append to specified buffer the text of the region.
     It is inserted into that buffer before its point.

     When calling from a program, give three arguments:
     a buffer or the name of one, and two character numbers
     specifying the portion of the current buffer to be copied."
       (interactive "BAppend to buffer: \nr")
       (let ((oldbuf (current-buffer)))
         (save-excursion
           (set-buffer (get-buffer-create buffer))
           (insert-buffer-substring oldbuf start end))))

  I want to know how can I use it?
  Thank you.

Re: How can I use fuction "append-to-buffer"?

[Wu XiaoGuang]

I just didn't know how to pass the two number argument(START and END) 
after "<ALT> x".
With your advice, I understand, just use mouse to "create" the "active 
mask" in oldbuf, then do "<ALT> x append-to-buffer buffer".
It works now.
Thank you!

Douglas Lewan wrote:
> Wu,
> 
> To use "append-to-buffer" interactively simply type "M-x 
> append-to-buffer" (where M-x is "<ESC> x" or possibly "<ALT> x").
> 
> To use it in another Emacs Lisp program:
> 1. Determine the BUFFER that you want to append to.
> 2. Calculate the START and END locations in the current buffer
>    that define the text to be appended.
> 3. In your defun simply write:
>        (append-to-buffer BUFFER START END)
> 
> I hope this helps.
>