window-tree

window-tree is a compiled Lisp function in `window.el'.

(window-tree &optional FRAME)

Return the window tree of frame FRAME.
FRAME must be a live frame and defaults to the selected frame.
The return value is a list of the form (ROOT MINI), where ROOT
represents the window tree of the frame's root window, and MINI
is the frame's minibuffer window.

If the root window is not split, ROOT is the root window itself.
Otherwise, ROOT is a list (DIR EDGES W1 W2 ...) where DIR is nil
for a horizontal split, and t for a vertical split. EDGES gives
the combined size and position of the child windows in the split,
and the rest of the elements are the child windows in the split.
Each of the child windows may again be a window or a list
representing a window split, and so on. EDGES is a list (LEFT
TOP RIGHT BOTTOM) as returned by `window-edges'.