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

#define NTHREADS 4

void* say_hello(void* arg) {
  printf("Hello World!\n");
  return NULL;
}


int main(int argc, char** argv) {
  pthread_t tid[NTHREADS];
  for(int i=0; i<NTHREADS; i++) {
    pthread_create(&tid[i], NULL, say_hello, NULL);    
  }

  for(int i=0; i<NTHREADS; i++) {
    pthread_join(tid[i], NULL);
  }

  return EXIT_SUCCESS;
}