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

void* thread_fn(void *arg)
{
        int id = (int)arg;
        printf("thread %d runs\n", id);
        return NULL;
}

int main()
{
        pthread_t t1, t2;

        pthread_create(&t1, NULL, thread_fn, (void*)1);
        pthread_create(&t2, NULL, thread_fn, (void*)2);

        pthread_join(t1, NULL);
        pthread_join(t2, NULL);
        return 0;
}