#include <gtk/gtk.h>

GdkPixbuf *create_pixbuf(const gchar * filename)
{
   GdkPixbuf *pixbuf;
   GError *error = NULL;
   pixbuf = gdk_pixbuf_new_from_file(filename, &error);
   if(!pixbuf) {
      fprintf(stderr, "%s\n", error->message);
      g_error_free(error);
   }

   return pixbuf;
}

int main( int argc, char *argv[])
{
  GtkWidget *window;

  gtk_init(&argc, &argv);

  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title(GTK_WINDOW(window), "icon");
  gtk_window_set_default_size(GTK_WINDOW(window), 230, 150);
  gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);

  GtkIconTheme* theme = gtk_icon_theme_get_default();
  static const char* kIconName = "chromium-browser";
  int size = 48;

  GtkIconInfo *icon_info = gtk_icon_theme_lookup_icon (theme, kIconName, size, GTK_ICON_LOOKUP_USE_BUILTIN);   

  g_print ("icon for %s at %dx%d is %s\n", kIconName, size, size,
            icon_info ? (gtk_icon_info_get_builtin_pixbuf (icon_info) ? "<builtin>" : gtk_icon_info_get_filename (icon_info)) : "<none>");

  const gchar *display_name = gtk_icon_info_get_display_name (icon_info);

  if (display_name)
     g_print ("Display name: %s\n", display_name);

  if (gtk_icon_theme_has_icon(theme, kIconName)) {
    printf("gtk_icon_theme_has_icon is true");

    GError *error;
    GdkPixbuf *pixbuf = gtk_icon_theme_load_icon (theme, kIconName, size,
                                         GTK_ICON_LOOKUP_USE_BUILTIN, &error);    
    gtk_window_set_icon(GTK_WINDOW(window), pixbuf);
    g_object_unref (pixbuf);
    // If either of these two commands is uncommented, the icon will reset to the "missing" icon.

    // #1
    // gtk_window_set_default_icon_name(kIconName);

    // #2
    // case where the first window created doesn't have an icon.
    gtk_window_set_icon_name(GTK_WINDOW(window), kIconName);
  } else {
    gtk_window_set_icon(GTK_WINDOW(window), create_pixbuf("chromium-browser.svg"));
  }
  gtk_widget_show(window);

  g_signal_connect_swapped(G_OBJECT(window), "destroy",
      G_CALLBACK(gtk_main_quit), NULL);

  gtk_main();

  return 0;
}