#include <atomic>
#include <memory>

std::shared_ptr<T>
pop()
{
  std::atomic<void*>& hp = get_hazard_pointer_for_current_thread();
  node* old_head         = head.load();
  do {
    node* temp;
    do {
      temp = old_head;
      hp.store(old_head);
      old_head = head.load();
    } while (old_head != temp);
  } while (old_head && !head.compare_exchange_strong(old_head, old_head->next));
  hp.store(nullptr);
  std::shared_ptr<T> res;
  if (old_head) {
    res.swap(old_head->data);
    if (outstanding_hazard_pointers_for(old_head)) {
      reclaim_later(old_head);
    }
    else {
      delete old_head;
    }
    delete_nodes_with_no_hazards();
  }
  return res;
}