    for (size_t sensor_id = 0;
         sensor_id < MAX_SENSORS; sensor_id++) {
        get_sensor_data(/*...*/);
    }

    int offset += output_json_sensors_start(
        buffer, buffer_size);
    for (size_t sensor_id = 0;
         sensor_id < MAX_SENSORS; sensor_id++) {
        if (need_output) {
            offset +=
                output_json_one_sensor(/*...*/);
        }
    }
    output_json_sensors_end(buffer, buffer_size,
                            offset);
