Multithreading in Z-Stack Linux Gateway 1.0.1

Hello,

I am a beginner here and working with Z-Stack HA sample application, and I want to know if I can use multithreading within the sample app.

I am registering a timer event in "int tcp_send_packet(server_details_t * server_details, uint8_t * buf, int len)" on a separate thread.

I don't want to send the next command unless there is 200ms gap between successive commands(since multiple commands aren't working and after reading throughout the forum I learned about the delay to be introduced) hence I am trying to do it by creating a thread to introduce the delay separately irrespective of execution hierarchy in Gateway sample app.

I have 3 questions.

1. Is multithreading going to work this way in this sample app ?

2. If yes, How/Where do I make changes to compile the code ? (I couldn't identify the spot where (in build_sample_app.c or in makefile) to add/link "-pthread" to compile it. I will take care of semaphores and concurrency once it is confirmed that it will work this way.)

3. Why doesn't it work this way ? What are my options ?

I have written this code

void delayTimerCb (void* arg)
{
    delayKill(&delayTimer);
    delayFlag = 0;
    exitFlag = 1;
}
void* thread_poll_delay (void* arg)
{
    delaySetTimer(&delayTimer, 200, false, delayTimerCb, NULL);
    
    delayFd = malloc(sizeof(struct pollfd));
    delayFd.fd = delayTimer.fd;
    delayFd.events = POLLIN;
    
    while(1)
    {
        if (!delayFlag)
        {
            break;
        }
        
        if ((poll(delayFd.fd, 1, -1)) > 0)
        {
            if (delayFd.revents & delayFd.events)
                delayFd.timer_handler_cb(delayFd.timer_handler_arg);
                
            if (exitFlag)
            {
                exitFlag = 0;
                break;    
            }
        }
        else
        {
            UI_PRINT_LOG("Delay fd not initialised")
            break;
        }
        
    }
    
}
int tcp_send_packet(server_details_t * server_details, uint8_t * buf, int len)
{
    
    FILE *tcp;
    
    pthread_attr_t attr;
    int p, s ;
    pthread_t threadID;
    /*
    s = pthread_attr_init(&attr);
    if (s != 0)
    {
        perror("pthread_attr_init");
        exit(-1);
    }
    */
    p = pthread_create(&threadID, NULL, thread_poll_delay, &variables);
    while(delayFlag);
    if (write(polling_fds[server_details->fd_index].fd, buf, len) != len)
    {
        return -1;
    }
    
    delayFlag = 1;
    tcp = fopen("/home/debian/Desktop/tcp.txt", "a+");
    fprintf(tcp, "Sending Packet Successful\n");
    fclose(tcp);
    return 0;
}

Thanks in advance