如何在C中获取gtk窗口的gdk窗口？

#include <gtk/gtk.h>
#include <gdk/gdk.h>

int main(int argc, char *argv[]) {
  GtkWidget *window;
  GdkWindow *gdk_window;
  GdkDisplay *gdk_display;
  GdkScreen *gdk_screen;

  gtk_init(&argc, &argv);

  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title(window, "Hello World");
  gtk_window_set_default_size(window, 200, 200);

  gdk_window = gdk_window_new(window);
  gdk_window_set_window_type(gdk_window, GDK_WINDOW_TOPLEVEL);
  gdk_window_set_decorated(gdk_window, FALSE);

  gdk_display = gdk_display_get_display(gdk_window);
  gdk_screen = gdk_display_get_screen(gdk_display);

  gdk_window_get_parent(gdk_window, (GdkWindow **)&gdk_window);

  gtk_main();

  return 0;
}