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

int main(int argc, char *argv[]) {
  Display *display;
  Window root;
  XColor color;
  int screen;

  if (argc < 2) {
    fprintf(stderr, "usage: %s color\n", argv[0]);
    exit(1);
  }

  if (!(display = XOpenDisplay(getenv("DISPLAY")))) {
    fprintf(stderr, "%s: unable to open display: %s\n", argv[0], getenv("DISPLAY"));
    exit(1);
  }

  screen = DefaultScreen(display);
  root = RootWindow(display, screen);

  XAllocNamedColor(display, DefaultColormap(display, screen), argv[1], &color, &color);
  XSetWindowBackground(display, root, color.pixel);
  XClearWindow(display, root);

  XFlush(display);
  XCloseDisplay(display);

  return 0;
}