gistfile1.c

struct baz
{
  pthread_mutex_t mutex;
  pthread_t thread;
  int statekeeping;
};

int
foo(void)
{
  struct baz *bar;
  if(!(bar = (struct baz *) calloc(1, sizeof(baz))) return -1;
  pthread_mutex_init(&(bar->mutex), NULL);
  pthread_mutex_lock(&(bar->mutex));
  pthread_create(&(bar->thread), NULL, mythread, bar);
  bar->statekeeping = 1;
  add_baz_to_global_list(bar);
  pthread_mutex_transfer(&(bar->mutex), bar->thread);
  return 0;
}

void *
mythread(void *arg)
{
  struct baz *bar;

  bar = (struct baz *) arg;
  pthread_mutex_lock(&(bar->mutex));
  bar->statekeeping = 2; /* up and running! */
  pthread_mutex_unlock(&(bar->mutex));
  /* do stuff */
  return NULL;
}

void *
some_other_thread(void *arg)
{
  struct baz *thingy;

  thingy = get_a_baz();
  pthread_mutex_lock(&(thingy->mutex));
  if(thingy->statekeeping == 1)
  {
     /* crazy limbo! wtf do we do now? */
  }
  else if(thingy->statekeeping == 2)
  {
     /* up and running! */
  }
  else
  {
      /* odd error condition */
  }
}