Как узнать имена/идентификаторы всех окон в fvwm?

polachok:~/sku% xwininfo 

xwininfo: Please select the window about which you
          would like information by clicking the
          mouse in that window.

xwininfo: Window id: 0x1c00004 "polachok@a1650g:~/sku | 63x56 | pts/11"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

static char buf[1024];
static Atom netwmname;
static Display *dpy;
static Window root;

static void
getname(Window w) {
	char **list = NULL;
	int n;
	XTextProperty prop;

	prop.nitems = 0;
	buf[0] = 0;
	XGetTextProperty(dpy, w, &prop, netwmname);
	if(!prop.nitems)
		XGetWMName(dpy, w, &prop);
	if(!prop.nitems)
		return;
	if(prop.encoding == XA_STRING)
		strncpy(buf, (char *)prop.value, sizeof(buf));
	else {
		if(XmbTextPropertyToTextList(dpy, &prop, &list, &n) >= Success
				&& n > 0 && *list)
		{
			strncpy(buf, *list, sizeof(buf));
			XFreeStringList(list);
		}
	}
	XFree(prop.value);
}

int
main(int argc, char *argv[]) {
	unsigned int i, num;
	Window *wins, d1, d2;
	XWindowAttributes wa;

	if((argc > 1) && !strncmp(argv[1], "-v", 3)) {
		fputs("lsw-"VERSION", (C)opyright MMVI Anselm R. Garbe\n", stdout);
		exit(EXIT_SUCCESS);
	}
	if(!(dpy = XOpenDisplay(0))) {
		fputs("lsw: cannot open display\n", stderr);
		exit(EXIT_FAILURE);
	}
	root = RootWindow(dpy, DefaultScreen(dpy));
	netwmname = XInternAtom(dpy, "_NET_WM_NAME", False);
	if(XQueryTree(dpy, root, &d1, &d2, &wins, &num)) {
		for(i = 0; i < num; i++) {
			if(!XGetWindowAttributes(dpy, wins[i], &wa))
				continue;
			if(wa.override_redirect)
				continue;
			getname(wins[i]);
			if(buf[0])
				fprintf(stdout, "%s\n", buf);
		}
	}
	if(wins)
		XFree(wins);
	XCloseDisplay(dpy);
	return 0;
}