Function: set-window-margins
set-window-margins is a function defined in window.c.
Signature
(set-window-margins WINDOW LEFT-WIDTH &optional RIGHT-WIDTH)
Documentation
Set width of marginal areas of window WINDOW.
WINDOW must be a live window and defaults to the selected one.
Second arg LEFT-WIDTH specifies the number of character cells to reserve for the left marginal area. Optional third arg RIGHT-WIDTH does the same for the right marginal area. A nil width parameter means no margin.
Leave margins unchanged if WINDOW is not large enough to accommodate margins of the desired width. Return t if any margin was actually changed and nil otherwise.
The margins specified by calling this function may be later overridden
by invoking set-window-buffer for the same WINDOW, with its
KEEP-MARGINS argument nil or omitted.
Probably introduced at or before Emacs version 21.1.
Source Code
// Defined in /usr/src/emacs/src/window.c
{
struct window *w = set_window_margins (decode_live_window (window),
left_width, right_width);
return w ? (apply_window_adjustment (w), Qt) : Qnil;
}