///  Define the listener function to be called after polling the temperature sensor.
static mut LISTENER: SensorListener = SensorListener {  //  Must be static so it won't go out of scope.
    sl_sensor_type: TEMP_SENSOR_TYPE,      //  Type of sensor: ambient temperature. Either computed (floating-point) or raw (integer)
    sl_func       : read_temperature,      //  Listener function to be called with the sensor data
    sl_arg        : LISTENER_CB,           //  Indicate to the listener function that this is a listener callback
    sl_next       : 0,                     //  Must be 0
};

///  Listen To Local Sensor
pub fn start_sensor_listener() -> i32 {
    ...
    //  Set the Listener Function to be called every 10 seconds, with the polled sensor data.
    let rc = unsafe { sensor_register_listener(listen_sensor, &mut LISTENER) };
    ...