无锁的生产者/消费者队列

我正在查看无锁队列的示例代码:

http://drdobbs.com/high-performance-computing/210604448?pgno=2

(也可以参考许多SO问题，例如在c++中是否有生产就绪的无锁队列或哈希实现)

这看起来应该适用于单个生产者/消费者，尽管代码中有许多错字。我已经将代码更新为如下所示，但是它在我身上崩溃了。有人知道为什么吗?

特别是，是否应该将divider和last声明为:

atomic<Node *> divider, last;    // shared

我在这台机器上没有支持c++ 0x的编译器，所以也许这就是我所需要的…

// Implementation from http://drdobbs.com/high-performance-computing/210604448
// Note that the code in that article (10/26/11) is broken.
// The attempted fixed version is below.
template <typename T>
class LockFreeQueue {
private:
    struct Node {
        Node( T val ) : value(val), next(0) { }
        T value;
        Node* next;
    };
    Node *first,      // for producer only
    *divider, *last;    // shared
public:
    LockFreeQueue()
    {
        first = divider = last = new Node(T()); // add dummy separator
    }
    ~LockFreeQueue()
    {
        while( first != 0 )    // release the list
        {
            Node* tmp = first;
            first = tmp->next;
            delete tmp;
        }
    }
    void Produce( const T& t )
    {
        last->next = new Node(t);    // add the new item
        last = last->next;      // publish it
        while (first != divider) // trim unused nodes
        {
            Node* tmp = first;
            first = first->next;
            delete tmp;
        }
    }
    bool Consume( T& result )
    {
        if (divider != last)         // if queue is nonempty
        {
            result = divider->next->value; // C: copy it back
            divider = divider->next;      // D: publish that we took it
            return true;                  // and report success
        }
        return false;                   // else report empty
    }
};

我写了下面的代码来测试它。Main(未显示)只调用TestQ()。

#include "LockFreeQueue.h"
const int numThreads = 1;
std::vector<LockFreeQueue<int> > q(numThreads);
void *Solver(void *whichID)
{
    int id = (long)whichID;
    printf("Thread %d initializedn", id);
    int result = 0;
    do {
        if (q[id].Consume(result))
        {
            int y = 0;
            for (int x = 0; x < result; x++)
            { y++; }
            y = 0;
        }
    } while (result != -1);
    return 0;
}

void TestQ()
{
    std::vector<pthread_t> threads;
    for (int x = 0; x < numThreads; x++)
    {
        pthread_t thread;
        pthread_create(&thread, NULL, Solver, (void *)x);
        threads.push_back(thread);
    }
    for (int y = 0; y < 1000000; y++)
    {
        for (unsigned int x = 0; x < threads.size(); x++)
        {
            q[x].Produce(y);
        }
    }
    for (unsigned int x = 0; x < threads.size(); x++)
    {
        q[x].Produce(-1);
    }
    for (unsigned int x = 0; x < threads.size(); x++)
        pthread_join(threads[x], 0);    
}

---

更新:最终崩溃是由队列声明引起的:

std::vector<LockFreeQueue<int> > q(numThreads);

当我将其更改为一个简单数组时，它运行良好。(我实现了一个带锁的版本，它也崩溃了。)我看到析构函数在构造函数之后立即被调用，导致双释放内存。但是，有人知道为什么析构函数会被std::vector立即调用吗?

last->next = new Node(t);    // add the new item
last = last->next;      // publish it