sd_rand example

Question

nRF SDK 17.1.0 with SD140 7.2.0 
 There is no example for how to use the sd_rand library. I've seen scant few posts that mention functions like sd_rand_application_bytes_available_get(), sd_rand_application_vector_get(), and the pool function, but there is no example for how to use this from start (in main) to finish (an array of randomly generated bytes). Could someone please show how this is done.

JGusler · Accepted Answer

Okay I did find something elsewhere, and this worked for me: 
 ret_val = sd_rand_application_bytes_available_get(&num_rand_bytes_available); APP_ERROR_CHECK(ret_val); 
 
 while (num_rand_bytes_available < ENCRYPTION_IV_SIZE) { // wait for SD to acquire enough random numbers sd_rand_application_bytes_available_get(&num_rand_bytes_available); } 
 ret_val = sd_rand_application_vector_get(iv, ENCRYPTION_IV_SIZE); APP_ERROR_CHECK(ret_val); 
 
 Where num_rand_bytes_available is only an initialized uint8_t with no value prior to these calls and ENCRYPTION_IV_SIZE is just a uint8_t of 16 (for my application) and iv is a uint8_t array of 16 values. I have NO idea why this works, I tried to look under the hood at the bytes_available_get but this is all I can find: 
 SVCALL(SD_RAND_APPLICATION_VECTOR_GET, uint32_t, sd_rand_application_vector_get(uint8_t * p_buff, uint8_t length)); 
 So to me this is still all hand wavey magic but it worked.