UNIX - Pridanie vlákien do programu.

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>

void *runner(void *param); /* the thread */

int main(int argc, char *argv[]) {

   //Verify two args were passed in
   if(argc < 2) {
      fprintf(stderr, "USAGE: ./prime.out <Integer value>\n");
      exit(1);
   }

   //verify the input is greater then or equal to two
   if(atoi(argv[1]) < 2) {
      fprintf(stderr, "USAGE: %d must be >= 2\n", atoi(argv[1]));
      exit(1);
   }

   pthread_t tid;       //Thread ID
   pthread_attr_t attr; //Set of thread attributes

   printf("Prime Numbers: ");

   //Get the default attributes
   pthread_attr_init(&attr);
   //Create the thread
   pthread_create(&tid,&attr,runner,argv[1]);
   //Wait for the thread to exit
   pthread_join(tid,NULL);
   printf("\nComplete\n");
}

//The thread will begin control in this function
void *runner(void *param) {
   int i,j,upper = atoi(param);
   /* Check to see if a number is prime */
   for(i = 2; i < upper; i++) {
   int trap = 0;
      /* Check each number for divisibility */
      for(j = 2; j < i; j++) {
         int result = i % j;
         /* If any of the numbers divide cleanly
             then this number is not prime. So
             stop checking. */
         if(result == 0) {
            trap = 1;
            break;
         }
      }
      //No numbers divided cleanly so this number must be prime
      if(trap == 0) {
         printf("[%d] ", i);
      }
   }
   //Exit the thread
   pthread_exit(0);
}