如何向此類添加複製構造函數和賦值運算符？

我無法將一個拷貝構造函數這個類： http://www.justsoftwaresolutions.co.uk/threading/implementing-a-thread-safe-queue-using-condition-variables.html 如何向此類添加複製構造函數和賦值運算符？

我需要補充它，這樣我可以在STL vector容器添加concurrent_queue。嘗試了下面，它幾乎編譯。實際上，如果我從複製構造函數中刪除the_mutex和the_condition_variable，它會進行編譯。當我將它添加回來時，它不會。關於編譯，賦值運算符似乎沒問題。

concurrent_queue(concurrent_queue<Data> const& rhs): 
    the_queue(rhs.the_queue), 
    the_mutex(rhs.the_mutex), 
    the_condition_variable(rhs.the_condition_variable) 
{ 
} 

concurrent_queue<Data>& operator = (concurrent_queue<Data> const& rhs) 
{ 
    if (this == &rhs) return *this; // check for self assignment 

    the_queue = rhs.the_queue; 
    the_mutex(rhs.the_mutex); 
    the_condition_variable(rhs.the_condition_variable); 
}

我得到的錯誤是：

concurrentqueue.h: In copy constructor ‘concurrent_queue<Data>::concurrent_queue(const concurrent_queue<Data>&) [with Data = Packet*]’: 
/usr/include/c++/4.4/bits/stl_construct.h:74: instantiated from ‘void std::_Construct(_T1*, const _T2&) [with _T1 = concurrent_queue<Packet*>, _T2 = concurrent_queue<Packet*>]’ 
/usr/include/c++/4.4/bits/stl_uninitialized.h:187: instantiated from ‘static void std::__uninitialized_fill_n<<anonymous> >::uninitialized_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = concurrent_queue<Packet*>*, _Size = long unsigned int, _Tp = concurrent_queue<Packet*>, bool <anonymous> = false]’ 
/usr/include/c++/4.4/bits/stl_uninitialized.h:223: instantiated from ‘void std::uninitialized_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = concurrent_queue<Packet*>*, _Size = long unsigned int, _Tp = concurrent_queue<Packet*>]’ 
/usr/include/c++/4.4/bits/stl_uninitialized.h:318: instantiated from ‘void std::__uninitialized_fill_n_a(_ForwardIterator, _Size, const _Tp&, std::allocator<_Tp2>&) [with _ForwardIterator = concurrent_queue<Packet*>*, _Size = long unsigned int, _Tp = concurrent_queue<Packet*>, _Tp2 = concurrent_queue<Packet*>]’ 
/usr/include/c++/4.4/bits/stl_vector.h:1035: instantiated from ‘void std::vector<_Tp, _Alloc>::_M_fill_initialize(size_t, const _Tp&) [with _Tp = concurrent_queue<Packet*>, _Alloc = std::allocator<concurrent_queue<Packet*> >]’ 
/usr/include/c++/4.4/bits/stl_vector.h:230: instantiated from ‘std::vector<_Tp, _Alloc>::vector(size_t, const _Tp&, const _Alloc&) [with _Tp = concurrent_queue<Packet*>, _Alloc = std::allocator<concurrent_queue<Packet*> >]’ 
test.cpp:18: instantiated from here 
concurrentqueue.h:24: error: no match for call to ‘(boost::mutex) (boost::mutex&)’

編輯：看來，升壓互斥繼承不可複製和條件變量，我認爲是一樣的。有趣的是，在作業中我可以複製它。爲什麼甚至會編譯？我是否需要擔心在使用它的情況下，它在實踐中是不可複製的？

來源

2010-11-01 Matt

無需編寫其中的任何一個：編譯器無論如何都會發出代碼來複製成員方面的代碼，如果它是合法的話。你需要做的是寫*法律*代碼，如其他答案所示。 – EJP 2010-11-01 03:17:19

boost::mutex和boost::condition_variable都只有默認構造函數。除此之外，你不希望他們的（可能被鎖定的）狀態被複制 - 只需使用默認的構造函數即可。

此外，您不應該直接複製the_queue，因爲這不是線程安全的。

來源

2010-11-01 03:14:25

AFAIK，boost::mutex和boost::condition不可複製（無論如何複製互斥鎖無意義）。使用默認構造函數在你的拷貝構造函數如下構建它們：

concurrent_queue(concurrent_queue<Data> const& rhs): 
    the_queue(rhs.the_queue), 
    the_mutex(), 
    the_condition_variable() 
{ 
}

注意，有problems與製作拷貝構造函數線程安全的。如果你不在線程之間複製對象，那應該不是問題。在您的previous question之後，所有concurrent_queue對象都是預先分配的想法之後，這應該不成問題。

來源

2010-11-01 03:14:33

如何向此類添加複製構造函數和賦值運算符？

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