add_callback

Description:

public void add_callback (owned DeviceListenerCB callback)

Adds an in-process callback function to an existing DeviceListener.

this	the DeviceListener instance to modify.
callback	an DeviceListenerCB function pointer.
callback_destroyed	A DestroyNotify called when the listener is freed and data associated with the callback should be freed. It can be NULL.
user_data	a pointer to data which will be passed to the callback when invoked.