c++ 11 多线线程系列--------使用锁和条件变量的线程安全队列

 c++ 11 多线线程系列--------使用锁和条件变量的线程安全队列

#include <iostream>
#include <thread>
#include <atomic>
#include <mutex>
#include <future>

#include <queue>
#include <mutex>
#include <condition_variable>
#include <memory>

template<typename T>
class threadsafe_queue
{
private:
  mutable std::mutex mut;
  std::queue<T> data_queue;
  std::condition_variable data_cond;
public:
  threadsafe_queue()
  {}

  void push(T new_value)
  {
    std::lock_guard<std::mutex> lk(mut);
    data_queue.push(std::move(new_value));
    data_cond.notify_one();
  }

  void wait_and_pop(T& value)
  {
    std::unique_lock<std::mutex> lk(mut);
    data_cond.wait(lk, [this]{return !data_queue.empty(); });
    value = std::move(data_queue.front());
    data_queue.pop();
  }

  std::shared_ptr<T> wait_and_pop()
  {
    std::unique_lock<std::mutex> lk(mut);
    data_cond.wait(lk, [this]{return !data_queue.empty(); });
    std::shared_ptr<T> res(
      std::make_shared<T>(std::move(data_queue.front())));
    data_queue.pop();
    return res;
  }

  bool try_pop(T& value)
  {
    std::lock_guard<std::mutex> lk(mut);
    if (data_queue.empty())
      return false;
    value = std::move(data_queue.front());
    data_queue.pop();
  }

  std::shared_ptr<T> try_pop()
  {
    std::lock_guard<std::mutex> lk(mut);
    if (data_queue.empty())
      return std::shared_ptr<T>();
    std::shared_ptr<T> res(
      std::make_shared<T>(std::move(data_queue.front())));
    data_queue.pop();
    return res;
  }

  bool empty() const
  {
    std::lock_guard<std::mutex> lk(mut);
    return data_queue.empty();
  }
};

int main()
{
  threadsafe_queue<int> rq;
}