Switching buffer to special mode or any mode?

Question

I have written some code to create a new buffer, it starts up in fundamental mode, the buffer is to display output from commands.

I am using this to create the buffer

(get-buffer-create "*My Buffer*")

Then I am trying to switch to and change the mode using this.

(display-buffer buffer-name)
(special-mode)

My understanding is that this should switch to the buffer and change the mode which is what actually happens with the added side effect the the original buffer I was using also switches to special-mode so both buffers end up in special-mode.

Am i doing this completely wrong ? how can i create a buffer for command output and change the mode of just that buffer ?

This is the working answer.

(display-buffer buffer-name)
(with-current-buffer buffer-name (special-mode))

Answer 1

The docstring of display-buffer says (C-h f display-buffer):

display-buffer is an interactive compiled Lisp function in `window.el'.

It is bound to C-x 4 C-o.

(display-buffer BUFFER-OR-NAME &optional ACTION FRAME)

Display BUFFER-OR-NAME in some window, without selecting it.

You have to select the buffer for following operations to act on it. See eg set-buffer or with-current-buffer.