steal_qdata

This function gets back user data pointers stored via g_object_set_qdata and removes the data from object without invoking its destroy function (if any was set).

Usually, calling this function is only required to update user data pointers with a destroy notifier, for example:

void
object_add_to_user_list (GObject     *object,
                         const gchar *new_string)
{
  // the quark, naming the object data
  GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
  // retrieve the old string list
  GList *list = g_object_steal_qdata (object, quark_string_list);

  // prepend new string
  list = g_list_prepend (list, g_strdup (new_string));
  // this changed 'list', so we need to set it again
  g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
  GList *node, *list = data;

  for (node = list; node; node = node->next)
    g_free (node->data);
  g_list_free (list);
}

Using get_qdata in the above example, instead of steal_qdata would have left the destroy function set, and thus the partial string list would have been freed upon set_qdata_full.

Parameters:

this	The GObject to get a stored user data pointer from
quark	A Quark, naming the user data pointer

Returns:

The user data pointer set, or null