(PECL gupnp >= 0.1.0)
gupnp_root_device_set_available — Set whether or not root_device is available
Controls whether or not root_device is available (announcing its presence).
A root device identifier, returned by gupnp_root_device_new().
Set TRUE if root_device should be available.
成功时返回 TRUE, 或者在失败时返回 FALSE.