Function: window-top-child
window-top-child is a function defined in window.c.
Signature
(window-top-child &optional WINDOW)
Documentation
Return the topmost child window of window WINDOW.
WINDOW must be a valid window and defaults to the selected one. Return nil if WINDOW is a live window (live windows have no children). Return nil if WINDOW is an internal window whose children form a horizontal combination.
Source Code
// Defined in /usr/src/emacs/src/window.c
{
struct window *w = decode_valid_window (window);
return WINDOW_VERTICAL_COMBINATION_P (w) ? w->contents : Qnil;
}