1112
Subj : Re: nptl and signals
To   : comp.programming.threads
From : divijbhatt@gmail.com
Date : Wed Jul 27 2005 04:08 am

Hi,
   Dear this is what I want to do

 void myflag(int sig)
 {
     sem_wait(&mysem);
         int ret;
         { printf("sgwait failed %d",ret); exit(0); }
         (void)time(&timeval);
         int s=0,mysig;
         int k =(int)pthread_getspecific(key);
        printf("In signal K:%d and thread id is:%lu time

taken:->%s\n",k,pthread_self(),ctime(&timeval));
         switch(k)
         {
           case 0:  printf("I am the main thread\t \n");
                    break;

           case 1:
                    cnt1=cnt1+1;
                    break;
           case 2:
                    cnt2=cnt2+1;
                    break;

           case 3:
                    cnt3=cnt3+1;
                    break;

       }
       printf("cnt1:%d\t cnt2:%d\t cnt3:%d\t",cnt1,cnt2,cnt3);
       sem_post(&mysem);
       return;
     }


 void *mytimer(void *argv)
 {
         int interval,ret,mysig;
         pthread_mutex_lock(&mylock);
         interval = *(int *)argv;
         free(argv);
         switch(interval)
         {
           case 1:
                   value.it_interval.tv_sec  = 1;
                   value.it_interval.tv_usec = 0;
                   value.it_value.tv_sec = 1;
                   value.it_value.tv_usec = 0;
                   setitimer(which,&value,NULL);
                   ret=pthread_setspecific(key,(void *)1);
                   if(ret!=0) {printf("Value cann't set\n"); exit(0); }
                   break;

           case 2:
                   value.it_interval.tv_sec = 2;
                   value.it_interval.tv_usec =0;
                   value.it_value.tv_sec = 1;
                   value.it_value.tv_usec = 0;
                   setitimer(which,&value,NULL);
                   ret=pthread_setspecific(key,(void *)2);
                   if(ret!=0) {printf("Value cann't set\n"); exit(0); }
                   break;

           case 3:
                   value.it_interval.tv_sec = 3;
                   value.it_interval.tv_usec = 0;
                   value.it_value.tv_sec = 1;
                   value.it_value.tv_usec = 0;
                   setitimer(which,&value,NULL);
                   ret=pthread_setspecific(key,(void *)3);
                   if(ret!=0) { printf("Value cann't set\n"); exit(0);
}
                   break;

         }

 pthread_mutex_unlock(&mylock);
 while(1);
 }

    int main()
  {
    int ret,*q,status,i=0;
    long int in;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED);
    memset(&mask,0,sizeof(mask));
    sigemptyset(&mask);
    sigaddset(&mask,SIGALRM);
    signal(SIGALRM,&myflag);
    ret = sem_init(&mysem,0,1);
    if(ret!=0){ printf("Semaph. cann't Initialize"); exit(0); }
    ret=pthread_key_create(&key,NULL);
    if(ret!=0)
    {  printf("Cann't create the key"); exit(0); }
    else
       printf("Key is created\n");
    ret=pthread_sigmask(SIG_BLOCK,&mask,NULL);
    if(ret!=0){ printf("Error in sigmask"); exit(0); }
    for(i=0;i<CNTR;i++)
    {
      q=(int *)malloc(sizeof(int));
      *q=i+1;
      ret=pthread_create(&tid[i],&attr,&mytimer,(void *)q);
      if(ret!=0) { printf("Error in thr creation%d",ret); exit(0); }

    }
    ret=sigwait(&mask,&sigint);
    if(ret!=0) { printf("sgwait failed %d",ret); exit(0); }
    printf("1:%d\t2:%d\t3:%d\t",cnt1,cnt2,cnt3);
    while(1);
    return;
   }

1.In the main program I am creating three detachable threads,before
creating them I am masking them but program is not running as I am
masking them before creating the threads.

2.In thread function I am using setitimer for each thread.Upon
expiration of timer SIGALRM is called which in turn called the signal
handler function.

3.In signal handler function I am incrementing the respective thread's
counter I have use semaphores there.

4.On return to main program I am printing the counters.

I run the program for a particular time and see the value of counters
counters that must be incremnted.For e.g if programe is run for 12
seconds then tha value of counter for each 1,2,3 thread must me 12,6,4
respectively.

Thanks in Advance
Divij

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