Basic Thread Management

struct thr_rtn {
  int completed;
  char in_msg[MAX_MSG];
  char out_msg[MAX_MSG];
};

main()
{
  pthread_t tid;
  int return_val;
  struct thr_rtn *ptr;
  struct thr_rtn msg;

  strcpy(msg.in_msg, "hello");
  msg.completed = 0;
  return_val = pthread_create(
    &tid, NULL,     thread1_func, &msg);
  return_val = pthread_join(tid, &ptr);
/* Now, ptr == &msg, 
  ptr->completed == 1,
  ptr->in_msg =="hello",
  ptr->out_msg == "hello" */
  exit(0);
}

void thread1_func(struct thr_rtn * msg)
{ 
  strcpy(msg->out_msg,
      msg->in_msg);
  msg->completed = 1;
  pthread_exit((void *) msg);
}