all repos — slstatus @ 39ee31c2425d3ff79f88808cabf44c305d6849ab

my build of slstatus (tools.suckless.org/slstatus/)

components/keyboard_indicators.c

/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <X11/Xlib.h>

#include "../util.h"

const char *
keyboard_indicators(void)
{
	Display *dpy;
	XKeyboardState state;

	if (!(dpy = XOpenDisplay(NULL))) {
		warn("XOpenDisplay: Failed to open display");
		return NULL;
	}
	XGetKeyboardControl(dpy, &state);
	XCloseDisplay(dpy);

	switch (state.led_mask) {
	case 1:
		return "c";
	case 2:
		return "n";
	case 3:
		return "cn";
	default:
		return "";
	}
}