static gboolean verbose;
static gboolean beep;
static gint     count;
 
static GOptionEntry main_entries[] =
  {
    { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose, "Be verbose", NULL },
    { NULL }
  };
 
static GOptionEntry add_entries[] =
  {
    { "beep", 'b', 0, G_OPTION_ARG_NONE, &beep, "Beep after adding", NULL },
    { NULL }
  };
 
static GOptionEntry remove_entries[] =
  {
    { "count", 'c', 0, G_OPTION_ARG_INT, &count, "Number of items to remove", "N" },
    { NULL }
  };
 
 
static gboolean
handle_add (gpointer data, GError **err)
{
  // implement the 'add' subcommand
  return TRUE;
}
 
static gboolean
handle_remove (gpointer data, GError **err)
{
  // implement the 'remove' subcommand
  return TRUE;
}
 
 
int
main (int argc, char *argv[])
{
  gboolean                   rv;
  GOptionContext            *o_ctx;
  GXSubCommandOptionContext *sc_ctx;
  GOptionGroup              *og;
  GError                    *err;
 
  o_ctx = g_option_context_new ("- add or remove items");
  g_option_context_add_main_entries (o_ctx, main_entries, "items");
 
  sc_ctx = gx_sub_command_option_context_new (o_ctx);
  
  og = g_option_group_new ("add", "the add subcommand", "add", NULL, NULL);
  g_option_group_add_entries (og, add_entries);
  gx_sub_command_option_context_add_group (sc_ctx, "add", og,
                                           (GXSubCommandFunc)handle_add, NULL);
 
  og = g_option_group_new ("remove", "the remove subcommand", "remove", NULL, NULL);
  g_option_group_add_entries (og, remove_entries);
  gx_sub_command_option_context_add_group (sc_ctx, "remove", og,
                                           (GXSubCommandFunc)handle_remove, NULL);
  err = NULL;
  rv = gx_sub_command_option_context_process (sc_ctx, &argc, &argv, &err);
  if (!rv)
    {
      g_printerr ("error: %s", err ? err->message : "something went wrong");
    }
 
  g_clear_error (&err);
  gx_sub_command_option_context_free (sc_ctx);
 
  return rv ? 0 : 1;
}