json-c-0.11 Thread safe?

[Mr.K]

Hi Team,

Need a clarification.

Currently I am working with json-c-0.11

https://github.com/json-c/json-c/tree/json-c-0.11

I am planning to use it in multithreaded program. Is it safe to use it in multi threaded programs?

Thanks

Kalai

[Eric Hawicz]

Do not use 0.11, it's ancient (8+ years old now) and there have been many bug fixes since then.

It might work, with the same caveats as https://groups.google.com/g/json-c/c/nfzf3XQWhng, but we're certainly not going to fix anything with that version if it doesn't work.

Eric

[Mr.K]

Hi Eric,

Thanks for your reply. I have downloaded the json-c-0.15 from https://github.com/json-c/json-c/tree/json-c-0.15 and have started building it.

I have observed few issues and I will send out a separate mail for clarification.

With respect to multi threading, my threads will have their own objects to work on and will not interfere with others.

Basically I am just converting the binary data to JSON. The below is a sample program which mimics our implementation.

Hopefully there is no issue with multithreading in below program even with json-c-0.11.

Also do we need to compile our code with ENABLE_THREADING option to be thread safe?

#include <json/json.h>

#include <stdio.h>

#include <string.h>

#include <pthread.h>

#define MAX_THREADS 10

#define MAX_MEMBERS 4

#define MAX_HOUSE 10

void create_json(json_object **streetarray)

{

        int i,j;

        for(i=0; i<MAX_HOUSE; i++)

        {

                json_object *houseobj = json_object_new_object();

                json_object_object_add(houseobj,"HouseName", json_object_new_string("Rose cottage"));

                json_object_object_add(houseobj,"NoOfMembers", json_object_new_int(MAX_MEMBERS));

                json_object_object_add(houseobj,"DoorNo", json_object_new_int(MAX_MEMBERS));

                json_object *membersarray= json_object_new_array();

                for(j=0; j<MAX_MEMBERS; j++)

                {

                        json_object *jobj = json_object_new_object();

                        json_object_object_add(jobj,"FirstName", json_object_new_string("Pat"));

                        json_object_object_add(jobj,"LastName", json_object_new_string("cummins"));

                        json_object_object_add(jobj,"Age", json_object_new_int(j+30));

                        json_object_array_add(membersarray, jobj);

                }

                json_object_object_add(houseobj, "members",membersarray);

                json_object *parent_houseobj = json_object_new_object();

                json_object_object_add(parent_houseobj, "house", houseobj);

                json_object_array_add(*streetarray, parent_houseobj);

        }

}

void* thread_main(void* threadid)

{

        json_object *strtobj   = json_object_new_object();

        json_object *strtarray = json_object_new_array();

        create_json(&strtarray);

        json_object_object_add(strtobj,"street", strtarray);

        printf("Thread %d prints\n %s\n", (int)threadid, json_object_to_json_string(strtobj));

        json_object_put(strtobj);

        return NULL;

}

int main()

{

        int i=0;

        pthread_t tid[MAX_THREADS];

        memset(&tid, sizeof(tid), 0);

        for(i=0; i<MAX_THREADS; i++)

        {

                int ret = pthread_create(&tid[i], NULL, thread_main, (void *)i);

                if(ret == 0)

                {

                        printf("Thread %d created\n",i);

                } else {

                        printf("failed to create thread %d\n",i);

                }

        }

        for(i=0; i<MAX_THREADS; i++)

        {

                pthread_join(tid[i],NULL);

        }

}

Thanks

[Eric Hawicz]

On Fri, Jul 23, 2021, 3:30 PM Mr.K <kalaim...@gmail.com> wrote:

Hi Eric,

...

Hopefully there is no issue with multithreading in below program even with json-c-0.11.

Also do we need to compile our code with ENABLE_THREADING option to be thread safe?

Since each thread is working with an entirely different set of json objects, it should be fine.  There is no need to set ENABLE_THREADING.

Eric

[Mr.K]

Thanks Eric. 

Appreciate your effort and contribution. You are amazing.

Thanks again.