利用原子变量的生产者消费者示例代码无法运行。

[aoaforever]

当我运行下面的代码时，程序无法得到任何输出，似乎是卡在了某个地方，请问是哪里出错了呢。
源出处

#include <iostream>
#include <thread>
#include <atomic>
#include <list>
#include <iostream>
using namespace std;


class Solution {
public:
  Solution()
  : state_{State::READ},
    trd_{[this]{
        this->customer();
            }
        }
    {     }

    void producer(int val)
    {
      while(state_.load(std::memory_order_acquire) == State::READ);

      task_.push_back(val);
      state_.store(State::WRITE, std::memory_order_release);
    }

    void customer() 
    { 
      while(state_.load(std::memory_order_acquire) == State::WRITE);
      if(!task_.empty()) { 
        int val = task_.front();
        cout<<val<<endl;
        task_.pop_front();
      }

      state_.store(State::READ, std::memory_order_release);
    }
private:
  enum class State {READ, WRITE};

  std::atomic<State> state_;
  std::thread        trd_;
  std::list<int>     task_;
};

int main(){
    Solution s;
    s.producer(2);
    s.producer(3);
    s.producer(1);
    return 0;
}

[ROBINwan999]

打印输出试试

[Norman-h]

首先 trd_ 线程只会调用 customer 函数一次，会错过运行的时机。Show you code

class Solution
{
public:
    Solution()
        : state_{State::READ},
          trd_{[this]
               {
                while (1) {
                    this->customer();
                }
                //    this->customer();
               }}
    {
    }

    ~Solution()
    {
        if (trd_.joinable()) {
            trd_.join();
        }
    }

    void producer(int val)
    {
        while (state_.load(std::memory_order_acquire) != State::READ) {
            std::this_thread::sleep_for(std::chrono::milliseconds(1));
        }

        task_.push_back(val);
        state_.store(State::WRITE, std::memory_order_release);
    }

    void customer()
    {
        while (state_.load(std::memory_order_acquire) != State::WRITE) {
            std::this_thread::sleep_for(std::chrono::milliseconds(1));
        }
        if (!task_.empty())
        {
            int val = task_.front();
            cout << val << endl;
            task_.pop_front();
        }
        state_.store(State::READ, std::memory_order_release);
    }

private:
    enum class State
    {
        READ,
        WRITE
    };

    std::atomic<State> state_;
    std::thread trd_;
    std::list<int> task_;
};