#include <X11/Xlib.h>
static Window
new_window(Display *d, const char *x)
{
   const int s = DefaultScreen(d);
   Window    w;

   w = XCreateSimpleWindow(d, RootWindow(d, s),
         0, 0, 200, 200, 1,
         BlackPixel(d, s),
         WhitePixel(d, s));
   XStoreName(d, w, x);
   return w;
}

int
main(void)
{
   Display *d;
   Window   w0, w1;

   d = XOpenDisplay(NULL);
   if (!d) return 1;

   w0 = new_window(d, "w0");
   w1 = new_window(d, "w1");

   XMapWindow(d, w1);
   XMapWindow(d, w0);

   for (;;) {
      XEvent e;

      XNextEvent(d, &e);
   }
   XCloseDisplay(d);
   return 0;
}