#include <X11/Xlib.h>
#include <stdio.h>

#define BREAK_MODULAR

#define ERROR(fmt, args...) do { \
	fprintf(stderr, fmt, ##args); \
	return -1; \
}while(0);

int main() {
	Display *dpy;
	int screen;
	Window root, wnd;
	XSetWindowAttributes attr;
	int flags = 0;

	dpy = XOpenDisplay(NULL);
	if (!dpy) ERROR("unable to open display");
	XSynchronize(dpy, True);

	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);
	if (root == None) ERROR("invalid root window\n");

	wnd = XCreateSimpleWindow(dpy, root, 0, 0, 640, 480, 0,
					BlackPixel(dpy, screen), WhitePixel(dpy, screen));
	if (wnd == None) ERROR("invalid window\n");
#ifdef BREAK_MODULAR
	XSelectInput(dpy, wnd, KeyPressMask);
#endif
	XMapRaised(dpy, wnd);
	
	while(1) {
		XEvent ev;
		XNextEvent(dpy, &ev);
		switch(ev.type) {
		case KeyPress:
			XCloseDisplay(dpy);
			return 0;
		default:
			break;
		}
	};
}