Programming

  void start_timer(void)
    {
       struct sigaction sa;
       struct itimerval timer;

       memset(&sa, 0, sizeof (sa));
 
       sa.sa_handler = &timer_handler;
       sa.sa_flags = SA_RESTART;  
       sigaction(SIGALRM, &sa, NULL);

       timer.it_value.tv_sec = 1;
       timer.it_value.tv_usec = 0;
 
       timer.it_interval.tv_sec = 1;
       timer.it_interval.tv_usec = 0;

       setitimer(ITIMER_REAL, &timer, NULL);
    }


    int main(int  argc, char *argv[])
    {
        //  write log entry
        //  check arguments to main
        //  read files containing parameters  of remote devices 
    
        //  initialise semaphores 
        sem_init(&semCounters, 0, 1);
        sem_init(&semPackets, 0, 1);
        sem_init(&semEvents, 0, 1);
        
        start_timer();
        pthread_create(&thread1, NULL, firstThread, NULL);
        pthread_create(&thread2, NULL, secondThread, NULL);
    
        while(1)
        {            
            //  infinite loop
        }
    
        return 0;
    }

sem_wait(&semCounters);
    counter.t4 = 0;
    sem_post(&semCounters);

void timer_handler(int signum)                                                  
{                                                                               
                                                                                
    pthread_t updateThread;                                                     
                                                                                
    sem_wait(&semCounters);                                                     
                                                                                
    counter.t1++;                                                               
    counter.t2++;                                                               
    counter.t3++;                                                               
    counter.t4++;                                                               
                                                                                
    if(counter.t4 >= 30 && flag == 1)                                           
    {                                                                           
        if(ret == 1)                                                            
        {                                                                       
            if(DEBUG)                                                           
            {                                                                   
                printf("GPRS General Interrogation RETRY flag set.\n");         
            }                                                                   
                                                                                
            counter.t4 = 0;                                                     
                                                                                
            pthread_create(&updateThread, NULL, thread3Function, NULL);         
        }                                                                       
                                                                                
        else                                                                    
        {                                                                       
            counter.t4 = 0;                                                     
        }                                                                       
    }                                                                           
    sem_post(&semCounters);                                                     
}