GNU Emacs Lisp Reference Manual

25.16: Window Configurations

A window configuration records the entire layout of a frame---all windows, their sizes, which buffers they contain, what part of each buffer is displayed, and the values of point and the mark. You can bring back an entire previous layout by restoring a window configuration previously saved.

If you want to record all frames instead of just one, use a frame configuration instead of a window configuration. See Frame Configurations.

Function: current-window-configuration

This function returns a new object representing Emacs's current window configuration, namely the number of windows, their sizes and current buffers, which window is the selected window, and for each window the displayed buffer, the display-start position, and the positions of point and the mark. An exception is made for point in the current buffer, whose value is not saved.

Function: set-window-configuration configuration

This function restores the configuration of Emacs's windows and buffers to the state specified by configuration. The argument configuration must be a value that was previously returned by current-window-configuration.

This function always counts as a window size change and triggers execution of the window-size-change-functions. (It doesn't know how to tell whether the new configuration actually differs from the old one.)

Here is a way of using this function to get the same effect as save-window-excursion:

(let ((config (current-window-configuration)))
  (unwind-protect
      (progn (split-window-vertically nil)
             ...)
    (set-window-configuration config)))

Special Form: save-window-excursion forms...

This special form records the window configuration, executes forms in sequence, then restores the earlier window configuration. The window configuration includes the value of point and the portion of the buffer that is visible. It also includes the choice of selected window. However, it does not include the value of point in the current buffer; use save-excursion if you wish to preserve that.

Don't use this construct when save-selected-window is all you need.

Exit from save-window-excursion always triggers execution of the window-size-change-functions. (It doesn't know how to tell whether the restored configuration actually differs from the one in effect at the end of the forms.)

The return value is the value of the final form in forms. For example:

(split-window)
     => #
(setq w (selected-window))
     => #
(save-window-excursion
  (delete-other-windows w)
  (switch-to-buffer "foo")
  'do-something)
     => do-something
     ;; The screen is now split again.

Function: window-configuration-p object

This function returns t if object is a window configuration.

Primitives to look inside of window configurations would make sense, but none are implemented. It is not clear they are useful enough to be worth implementing.