C++实现消息队列模板类

template <class T>
class MessageQueue
{
public:
    void push(const T &msg)
    {
        std::unique_lock<std::mutex> lck(m_mtx);
        m_queue.push(msg);
        m_cv.notify_one();
    }
    bool poll(T &msg)
    {
        std::unique_lock<std::mutex> lck(m_mtx);
        if (m_queue.size())
        {
            msg = m_queue.front();
            m_queue.pop();
            return true;
        }
        return false;
    }
    void wait(T &msg)
    {
        std::unique_lock<std::mutex> lck(m_mtx);
        while (!m_queue.size())
            m_cv.wait(lck);
        msg = m_queue.front();
        m_queue.pop();
    }
    size_t size()
    {
        std::unique_lock<std::mutex> lck(m_mtx);
        return m_queue.size();
    }

private:
    std::queue<T> m_queue;
    std::mutex m_mtx;
    std::condition_variable m_cv;
};