Function: other-buffer

other-buffer is a function defined in buffer.c.

Signature

(other-buffer &optional BUFFER VISIBLE-OK FRAME)

Documentation

Return most recently selected buffer other than BUFFER.

Buffers not visible in windows are preferred to visible buffers, unless optional second argument VISIBLE-OK is non-nil. Ignore the argument BUFFER unless it denotes a live buffer. If the optional third argument FRAME specifies a live frame, then use that frame's buffer list instead of the selected frame's buffer list.

The buffer is found by scanning the selected or specified frame's buffer list first, followed by the list of all buffers. If no other buffer exists, return the buffer *scratch* (creating it if necessary).

Probably introduced at or before Emacs version 16.

Source Code

// Defined in /usr/src/emacs/src/buffer.c
{
  struct frame *f = decode_live_frame (frame);
  Lisp_Object tail = f->buffer_list, pred = f->buffer_predicate;
  Lisp_Object buf, notsogood = Qnil;

  /* Consider buffers that have been seen in the frame first.  */
  for (; CONSP (tail); tail = XCDR (tail))
    {
      buf = XCAR (tail);
      if (candidate_buffer (buf, buffer)
	  /* If the frame has a buffer_predicate, disregard buffers that
	     don't fit the predicate.  */
	  && (NILP (pred) || !NILP (call1 (pred, buf))))
	{
	  if (!NILP (visible_ok)
	      || NILP (Fget_buffer_window (buf, Qvisible)))
	    return buf;
	  else if (NILP (notsogood))
	    notsogood = buf;
	}
    }

  /* Consider alist of all buffers next.  */
  FOR_EACH_LIVE_BUFFER (tail, buf)
    {
      if (candidate_buffer (buf, buffer)
	  /* If the frame has a buffer_predicate, disregard buffers that
	     don't fit the predicate.  */
	  && (NILP (pred) || !NILP (call1 (pred, buf))))
	{
	  if (!NILP (visible_ok)
	      || NILP (Fget_buffer_window (buf, Qvisible)))
	    return buf;
	  else if (NILP (notsogood))
	    notsogood = buf;
	}
    }

  if (!NILP (notsogood))
    return notsogood;
  else
    {
      AUTO_STRING (scratch, "*scratch*");
      buf = Fget_buffer (scratch);
      if (NILP (buf))
	{
	  buf = Fget_buffer_create (scratch, Qnil);
	  Fset_buffer_major_mode (buf);
	}
      return buf;
    }
}