desktop: +xkbledq

README.md

@@ -184,6 +184,7 @@ Contents - links to doc section for each script here:
         - [exclip](#hdr-exclip)
         - [xdpms](#hdr-xdpms)
         - [xiwait](#hdr-xiwait)
+        - [xkbledq](#hdr-xkbledq)
         - [rss-get](#hdr-rss-get)
         - [qr](#hdr-qr)
         - [gtk-color-calc](#hdr-gtk-color-calc)
@@ -3757,6 +3758,19 @@ Build with: `gcc -O2 -lX11 -lXi -Wall xiwait.c -o xiwait && strip xiwait`
 
 Also same as xdpms - should probably only work on Xorg systems, not wayland.
 
+<a name=hdr-xkbledq></a>
+##### [xkbledq](desktop/xkbledq.c)
+
+Very simple C binary to query X11 keyboard (XKB) LED state(s),
+either printing them or returning state via exit code=43 if LED is enabled.
+
+Build with: `gcc -O2 -lX11 -Wall xkbledq.c -o xkbledq && strip xkbledq`\
+Usage: `xkbledq` (print enabled LEDs), `xkbledq scroll` (return 43 if scroll lock enabled).
+
+Intended for checking whether specific mode should be enabled depending on
+user-visible keyboard LED state (if/when it's used as a simple indicator),
+e.g. swap xmodmap layout depending on Scroll Lock mode.
+
 <a name=hdr-rss-get></a>
 ##### [rss-get](desktop/rss-get)
 

desktop/xkbledq.c

@@ -0,0 +1,45 @@
+// Small standalone C binary to query/print keyboard LED state(s)
+// Build with: gcc -O2 -lX11 -Wall xkbledq.c -o xkbledq && strip xkbledq
+// Usage info: ./xkbledq -h
+
+#include <stdio.h>
+#include <string.h>
+
+#include <X11/Xlib.h>
+#include <X11/XKBlib.h>
+
+#define err_unless(chk) if (!(chk)) { err = "'" #chk "' failed"; goto cleanup; }
+
+int main(int argc, char *argv[]) {
+	if (argc > 2) {
+		printf("Usage: %s [-h/--help] [led]\n", argv[0]);
+		printf("Show/query named keyboard LED state(s).\n");
+		printf( "When querying, returns 1 for e.g."
+			" \"%s scroll\" if scroll lock LED is lit, 0 otherwise.\n", argv[0] );
+		return 1; }
+	char *query = "";
+	if (argc == 2) query = argv[1];
+
+	char *err = NULL;
+	Display *dpy = NULL;
+	int xkb_opcode, xkb_event, xkb_error;
+	int xkb_lmaj = XkbMajorVersion, xkb_lmin = XkbMinorVersion;
+	err_unless(dpy = XOpenDisplay(NULL));
+	err_unless(XkbLibraryVersion(&xkb_lmaj, &xkb_lmin));
+	err_unless(XkbQueryExtension(dpy, &xkb_opcode, &xkb_event, &xkb_error, &xkb_lmaj, &xkb_lmin));
+
+	char atoms[][12] = {"Caps Lock", "Num Lock", "Scroll Lock"};
+	char leds[][7] = {"caps", "num", "scroll"};
+
+	Bool st;
+	for (size_t n = 0; n <= 2; n++) {
+		XkbGetNamedIndicator(dpy, XInternAtom(dpy, atoms[n], False), NULL, &st, NULL, NULL);
+		if (!st) continue;
+		if (strlen(query)) { if (!strcmp(query, leds[n])) return 43; }
+		else puts(leds[n]); }
+
+	cleanup:
+	if (dpy) XCloseDisplay(dpy);
+	if (err) { fprintf(stderr, "ERROR: %s\n", err); return 1; }
+	return 0;
+}