#include <X11/Xlib.h>

int main()
{
	Display *dpy = XOpenDisplay (0);
	Window w = XCreateSimpleWindow (dpy, DefaultRootWindow(dpy),
			0, 0, 256, 256, 0, 0, 0);
	Pixmap pix = XCreatePixmap (dpy, w, 256, 256,
			DefaultDepth(dpy, DefaultScreen(dpy)));
	GC gc = XCreateGC (dpy, pix, 0, 0);
	XSetForeground (dpy, gc, 0xffffffff);
	XFillRectangle (dpy, pix, gc, 0, 0, 256, 256);
	XSetForeground (dpy, gc, 0);
	XDrawRectangle (dpy, pix, gc, 0, 0, 256, 256);
	XDrawLine (dpy, pix, gc, 0, 0, 256, 256);
	XDrawLine (dpy, pix, gc, 256, 0, 0, 256);
	XFreeGC (dpy, gc);
	XSetWindowBackgroundPixmap (dpy, w, pix);
	XMapWindow (dpy, w);

	XEvent event;
	do
		XNextEvent (dpy, &event);
	while (event.type != DestroyNotify);
}