Getting segmentation fault while accessing null values

[Suryaveer]

I am bignner in C and was looking for some simple json api in C and found this the simplest of all. So, thanks for that.

Now, the problem. I am obviously trying to parse the json to an struct. What I am trying to do is to get the item name in the loop instead of hardcoding like in cJSON_GetObjectItem(record,"domain")->valuestring. I understand that there's no direct api to fetch the item names so what I tried my best to understand the cJSON and came up with this:

int parse_json_to_result(char *json, db_res_t** result) {
    cJSON *root, *record;
    int recourdCount = 0;
    int i = 0;
    int value = 0;
    int int_val=0;
    char *str_val='\0';

    root = cJSON_Parse(json);
    recourdCount = cJSON_GetArraySize(root);
    printf("array size: %d\n", recourdCount);

    *result = malloc(sizeof(db_res_t));
    (*result)->rows =malloc(sizeof(db_row_t)*recourdCount);

    for(i=0;i<recourdCount;i++)
    {
        record = cJSON_GetArrayItem(root, i);
        (*result)->rows[i].values = malloc(sizeof(db_val_t));

        cJSON *subitem = record-> child;
        while(subitem)
        {
//This works fine for null.
        printf("domain: %s\n",cJSON_GetObjectItem(record,"domain")->valuestring);
//This fails if value is null.
        //  printf("%s\t:",subitem->string);
            if(subitem->type == cJSON_Number)
            {
                int_val =  cJSON_GetObjectItem(record,subitem->string)->valueint;
                printf("%d\n",int_val);
                (*result)->rows[i].values->val.int_val = int_val;
            }
            else
            {
                str_val =  cJSON_GetObjectItem(record,subitem->string)->valuestring;
                printf("%s\n",str_val);
                (*result)->rows[i].values->val.str_val.s = str_val;
            }
        subitem = subitem->next;
        }
    }
free(root);
return 1;
}

Above code works as expected until it encounters values which are null. ""
[{"username":"ubuntu","domain":"192.168.254.129"}] // this works
[{"username":"ubuntu","domain":""}] // this works
[{"username":"ubuntu","domain":null}] // this fails

Is this the expected behaviour or I am missing something in the code?
I tried to understand in the code but I am still not that expert in C to understand this code. Please help me here.

Thanks