pthread

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define NUM_THREADS 16
/**********************************
 * compilare con                  *
 * cc pthread.c -pthread -lm    *
 **********************************/
void *operaio(void *t)
{
   int i;
   long n;
   pthread_t ThId= pthread_self();
   double risultato=0.0;
   n = (long)t;
   printf("Thread numero %ld (con ThreadID %ld) partito...\n",n,ThId);
   for (i=0; i<1000000; i++)
   {
      risultato = risultato + sin(i) * tan(i);
   }
   printf("Thread %ld terminato. Risultato = %e\n",n, risultato);
   pthread_exit((void*) t);
}

int main (int argc, char *argv[])
{
   pthread_t thread[NUM_THREADS];
   int ret;long t;
   void *status;

   /* Boss: inizializza i thread  */
   for(t=0; t<NUM_THREADS; t++) {
      printf("Main: creating thread %ld\n", t);
      ret = pthread_create(&thread[t], NULL, operaio, (void *)t);
      if (ret) {printf("ERR: pthread_create() ha restituito %d\n", ret);
         exit(-1);}
      }

   /* Boss: aspetta il termine dei thread */
   for(t=0; t<NUM_THREADS; t++) {
      ret = pthread_join(thread[t], &status);
      if (ret) {printf("ERR: pthread_join() ha restituito %d\n", ret);
         exit(-1);}
      printf("main(): riunito thread %ld (status=%ld)\n",t,(long)status);
      }

printf("main(): fine esecuzione.\n");
pthread_exit(EXIT_SUCCESS);
}