xcb D example program

module std.c.linux.X11.xcb.example;

/* build with: dmd  xcb.d xproto.d example.d -L-lxcb */

import std.stdio;
import std.c.linux.X11.xcb.xcb;
import std.c.linux.X11.xcb.xproto;
import std.c.stdlib;
int main()
{
  xcb_connection_t    *c;
  xcb_screen_t        *s;
  xcb_window_t         w;
  xcb_gcontext_t       g;
  xcb_generic_event_t *e;
  uint                 mask;
  uint                 values[2];
  int                  done = 0;
  static xcb_rectangle_t      r = { 20, 20, 60, 60 };

                       /* open connection with the server */
  c = xcb_connect(null, null);
  if (xcb_connection_has_error(c)) {
    writefln("Cannot open display");
    return 1;
  }
                       /* get the first screen */
  auto iter = xcb_setup_roots_iterator(xcb_get_setup(c));
  s = iter.data;

  w = iter.data.root;


                       /* create black graphics context */
  g = xcb_generate_id(c);
  mask = XCB_GC_FOREGROUND | XCB_GC_GRAPHICS_EXPOSURES;
  values[0] = (*s).white_pixel;
  values[1] = 0;
  xcb_create_gc(c, g, s.root, mask, &values[0]);

                       /* create window */
  w = xcb_generate_id(c);
  mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
  values[0] = s.white_pixel;
  values[1] = XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS;
  xcb_create_window(c, s.root_depth, w, s.root,
                  10, 10, 100, 100, 1,
                  XCB_WINDOW_CLASS_INPUT_OUTPUT, s.root_visual,
                  mask, &values[0]);

  writeln("test");                     /* map (show) the window */
  xcb_generic_error_t *err = xcb_request_check(c, xcb_map_window_checked(c, w));
  if(err)
        writeln("there was an error mapping the window");
        //writeln(e.error_code);
  xcb_flush(c);

                       /* event loop */

  do{
    e = xcb_wait_for_event(c);
    if(!e)break;
    switch (e.response_type & ~0x80) {
    case XCB_EXPOSE:    /* draw or redraw the window */
      xcb_poly_fill_rectangle(c, w, g,  1, &r);
      xcb_flush(c);
      break;
    case XCB_KEY_PRESS:  /* exit on key press */
      done = 1;
      break;
    default:
      break;
    }
    free(e);
  }while(!done);
                       /* close connection to server */
  xcb_disconnect(c);

  return 0;
}