move focus between sub-windows (or buffers?) with ctrl-tab?

Question

Currently using GNU Emacs 23.1.1.

I've used xemacs since the late 90s and am only now switching to proper emacs.

If I had my xemacs window split into a top buffer and bottom buffer, I could move the keyboard focus between them with ctrl-tab. (I cannot remember if that's something I wrote myself 20+ years ago, or was a standard mapping, but checking my config files I don't think I wrote it myself.)

There are similar questions about rotating between buffers, but, I think, keeping the focus in the same sub-window. That's not my question, but just to be clear, the following is something I find very useful but isn't what this current question is asking. I probably have the wrong terminology, but the following code changes the buffer within the current sub-window. Instead I want to leave all the sub-windows looking at their current buffers, and instead move focus to the next sub-wind.

(defun switch-to-next-buffer () (interactive) (switch-to-buffer (other-buffer)))

Answer 1

Gnu Emacs has the function other-window which is bound to C-x o.

The relevant section from the doc string of other-window:

(other-window COUNT &optional ALL-FRAMES)
...
Select another window in cyclic ordering of windows. COUNT specifies the number of windows to skip, starting with the selected window, before making the selection. If COUNT is positive, skip COUNT windows forwards. If COUNT is negative, skip -COUNT windows backwards. COUNT zero means do not skip any window, so select the selected window. In an interactive call, COUNT is the numeric prefix argument.

So the keysequence C-<minus> C-x o gives you the inverse of C-x o. Note that C-<minus> stands for the numeric prefix arg -1.