如何向此类添加复制构造函数和赋值运算符？

我无法将一个拷贝构造函数这个类： http://www.justsoftwaresolutions.co.uk/threading/implementing-a-thread-safe-queue-using-condition-variables.html 如何向此类添加复制构造函数和赋值运算符？

我需要补充它，这样我可以在STL vector容器添加concurrent_queue。尝试了下面，它几乎编译。实际上，如果我从复制构造函数中删除the_mutex和the_condition_variable，它会进行编译。当我将它添加回来时，它不会。关于编译，赋值运算符似乎没问题。

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); 
}

我得到的错误是：

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&)’

编辑：看来，升压互斥继承不可复制和条件变量，我认为是一样的。有趣的是，在作业中我可以复制它。为什么甚至会编译？我是否需要担心在使用它的情况下，它在实践中是不可复制的？

来源

2010-11-01 Matt

无需编写其中的任何一个：编译器无论如何都会发出代码来复制成员方面的代码，如果它是合法的话。你需要做的是写*法律*代码，如其他答案所示。 – EJP 2010-11-01 03:17:19

boost::mutex和boost::condition_variable都只有默认构造函数。除此之外，你不希望他们的（可能被锁定的）状态被复制 - 只需使用默认的构造函数即可。

此外，您不应该直接复制the_queue，因为这不是线程安全的。

来源

2010-11-01 03:14:25

AFAIK，boost::mutex和boost::condition不可复制（无论如何复制互斥锁无意义）。使用默认构造函数在你的拷贝构造函数如下构建它们：

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

注意，有problems与制作拷贝构造函数线程安全的。如果你不在线程之间复制对象，那应该不是问题。在您的previous question之后，所有concurrent_queue对象都是预先分配的想法之后，这应该不成问题。

来源

2010-11-01 03:14:33

如何向此类添加复制构造函数和赋值运算符？

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