c++ - 线程安全队列给出段错误

Question

我正在编写一个线程安全队列来添加字符串流对象。我认为发生段错误是因为 stringstream ss 在添加到队列时被销毁了，但如您所见，我正在使用 std::move()

#include <iostream>
#include <mutex>
#include <sstream>
#include <queue>
#include <condition_variable>

template <typename T>
class ThreadSafeQueue
{
public:
    /* 
        Returns the front element and removes it from the collection
        No exception is ever returned as we garanty that the deque is not empty
        before trying to return data.
        This is useful in our while loop renderer, because it just waits if there
        are no members to be popped.
    */
    T pop(void) noexcept
    {
        std::unique_lock<std::mutex> lock{_mutex};

        while (_collection.empty())
        {
            _condNewData.wait(lock);
        }
        auto elem = std::move(_collection.front());
        _collection.pop();
        return elem;
    }
    template <typename... Args>
    void emplace(Args &&... args)
    {
        addDataProtected([&] {
            _collection.emplace(std::forward<Args>(args)...);
        });
    }

private:
    /*
        Locks the thread and do something with the deque. 
        Then unique_lock goes away and unlocks the thread
    */
    template <class F>
    decltype(auto) lockAndDo(F &&fct)
    {
        std::unique_lock<std::mutex> lock{_mutex};
        return fct();
    }

    template <class F>
    void addDataProtected(F &&fct)
    {
        lockAndDo(std::forward<F>(fct));
        _condNewData.notify_one();
    }

private:
    std::queue<T> _collection;            // Concrete, not thread safe, storage.
    std::mutex _mutex;                    // Mutex protecting the concrete storage
    std::condition_variable _condNewData; // Condition used to notify that new data are available.
};

int main()
{
    std::unique_ptr<ThreadSafeQueue<std::stringstream>> logMessages;
    std::stringstream ss;
    ss << "hello";
    logMessages->emplace(std::move(ss));
    return 0;
}

Answer 1

std::unique_ptr<ThreadSafeQueue<std::stringstream>> logMessages;

您从未为此变量分配内存。它没有指向 ThreadSafeQueue<>对象

也许

auto logMessages = std::make_unique<ThreadSafeQueue<std::stringstream>>();

代替？

或者按照评论中的建议制作普通对象。