diff -u slock-0.6/slock.c slock-0.6-xid/slock.c
--- slock-0.6/slock.c	2007-03-07 07:31:44.000000000 -0500
+++ slock-0.6-xid/slock.c	2007-11-04 22:28:22.898088945 -0500
@@ -104,6 +104,11 @@
 	len = 0;
 	XSync(dpy, False);
 
+	if((argc > 1) && !strncmp(argv[1], "-w", 3)) {
+		printf("0x%x\n", w);
+		fflush(stdout);
+	}
+
 	/* main event loop */
 	while(running && !XNextEvent(dpy, &ev))
 		if(ev.type == KeyPress) {