Thanks for your reply.
Yes, the returned value of "bsec_iot_init" is 0.
/* Call to the function which initializes the BSEC library
* Switch on low-power mode and provide no temperature offset */
ret = bsec_iot_init(BSEC_SAMPLE_RATE_LP, 0.0f, bus_write, bus_read, sleep, state_load, config_load);
/* Could not intialize BME680 */
else if (ret.bsec_status)
/* Could not intialize BSEC library */
/* Call to endless loop function which reads and processes data based on sensor settings */
/* State is saved every 10.000 samples, which means every 10.000 * 3 secs = 500 minutes */
bsec_iot_loop(sleep, get_timestamp_us, output_ready, state_save, 10000);
I setup SW environment on STM32 and run bsec_iot_example.c. I found that the my code couldn't output the correct BSEC result at first. After I check code in example, the stack size of the system should be increased, otherwise the example code will not work properly.
Attachment is my code, you could refer them.