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

int square (int x)
{
  return (x * x);
}

void *my_thread(void *arg)
{
    int x = 0;
    int sqr;

    while (true) {
        sqr = square(5);
        sleep(1);
    }
    return NULL;
}

int main()
{
    pthread_t thread_id;
    if (pthread_create(&thread_id, NULL, my_thread, NULL)) {
        fprintf(stderr, "Error creating thread\n");
        return 1;
    }
    if (pthread_join(thread_id, NULL)) {
         fprintf(stderr, "Error joining thread\n");
         return 2;
    }
    return 0;
}