线程安全的有界队列在 Boost 1.54 中挂起

以下用于有界线程安全队列的代码在 Boost 1.49 中按预期工作。但是，更新到 Boost 1.54 后，代码不再按预期运行。也就是说，当缓冲区为空(满(时，消费者线程(生产者线程(永远等待m_not_empty(m_not_full(条件变量并且永远不会唤醒(我认为是因为生产者线程没有互斥锁(。

版本 1.54 中是否有一些更改可能会破坏代码？或者，也许，我错过的代码中有错误？

#include <iostream>
#include <boost/circular_buffer.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>
#include <boost/thread/thread.hpp>
template <class T>
class bounded_buffer {
public:
    bounded_buffer(size_t capacity) {cb.set_capacity(capacity);}
    void push(T item) {
        boost::mutex::scoped_lock lock(m_mutex);
        while (cb.full()) {
            m_not_full.wait(lock);
        }
        cb.push_back(item);
        lock.unlock();
        m_not_empty.notify_one();
    }
    void pop(T &pItem) {
        boost::mutex::scoped_lock lock(m_mutex);
        while (cb.empty()) {
            m_not_empty.wait(lock);
        }
        pItem = cb.front();
        cb.pop_front(); 
        lock.unlock();
        m_not_full.notify_one();
    }
private:     
    boost::mutex m_mutex;
    boost::condition m_not_empty;
    boost::condition m_not_full;
    boost::circular_buffer<T> cb;
};
bounded_buffer<int> bb_int(4);
void producer() {
    int i = 10;
    for(int j=0; j<100; ++j) {
        bb_int.push(i);
        std::cout << "producer: " << i << std::endl;
        i++;
    }
}
void consumer() {
    int i;
    for(int j=0; j<100; ++j) {
        bb_int.pop(i);
        std::cout << "consumer: " << i << std::endl;
    }
}
// Test code
int main() {
    // Start the threads.
    boost::thread consume(consumer);
    boost::thread produce(producer);
    // Wait for completion.
    consume.join();
    produce.join();
}