错误C2582：'bitstream::bitset_extractor<T> =‘函数在’bitstream：：bitset_extractor<T> VS 2010‘中不可用

Question

我面临着奇怪的problem.Same代码在vs 2008和VS 2010 Debug和Dubug 版本中运行良好，但是在发布和发布的Unicode中编译失败。这可能是什么原因。

此代码正在生成错误。

struct bitset_extractor
{
    typedef std::forward_iterator_tag   iterator_category;
    typedef T                           value_type;
    typedef T*                          pointer;
    typedef T&                          reference;
    typedef ptrdiff_t                   difference_type;

    bitset_extractor(const boost::dynamic_bitset<T>& bs, T *buffer)
        : bs_(bs), buffer_(buffer), current_(0)
    {}

    bitset_extractor(const bitset_extractor& it)
        : bs_(it.bs_), buffer_(it.buffer_), current_(it.current_)
    {}

    T& operator*()
    {
        return buffer_[current_];
    }

    bitset_extractor& operator++()
    {
        ++current_;
        return *this;
    }
   private:
    void operator=(T const&);           // unimplemented

    const boost::dynamic_bitset<T>&     bs_;
    T * const                           buffer_;
    unsigned int                        current_;
};

1>C:\Program Files\Microsoft Visual Studio 10.0\VC\include\xutility(275): error C2679: binary '=' : no operator found which takes a right-hand operand of type 'bitstream::bitset_extractor<T>' (or there is no acceptable conversion)
1>          with
1>          [
1>              T=uint8_t
1>          ]
1>           C:\vikram\Project\Seurat\src\app\logitech\LogiRTP\Library\Filters\plc\common\bitstream.h(195): could be 'void bitstream::bitset_extractor<T>::operator =(const T &)'
1>          with
1>          [
1>              T=uint8_t
1>          ]
1>          while trying to match the argument list '(bitstream::bitset_extractor<T>, bitstream::bitset_extractor<T>)'
1>          with
1>          [
1>              T=uint8_t
1>          ]
1>          C:\Program Files\Microsoft Visual Studio 10.0\VC\include\xutility(2176) : see reference to function template instantiation '_Iter &std::_Rechecked<_OutIt,_OutIt>(_Iter &,_UIter)' being compiled
1>          with
1>          [
1>              _Iter=bitstream::bitset_extractor<uint8_t>,
1>              _OutIt=bitstream::bitset_extractor<uint8_t>,
1>              _UIter=bitstream::bitset_extractor<uint8_t>
1>          ]
1>          C:\vikram\Project\Seurat\3rdparty\boost\boost/dynamic_bitset/dynamic_bitset.hpp(1090) : see reference to function template instantiation '_OutIt std::copy<std::_Vector_const_iterator<_Myvec>,BlockOutputIterator>(_InIt,_InIt,_OutIt)' being compiled
1>          with
1>          [
1>              _OutIt=bitstream::bitset_extractor<uint8_t>,
1>              _Myvec=std::_Vector_val<unsigned char,std::allocator<uint8_t>>,
1>              BlockOutputIterator=bitstream::bitset_extractor<uint8_t>,
1>              _InIt=std::_Vector_const_iterator<std::_Vector_val<unsigned char,std::allocator<uint8_t>>>
1>          ]
1>          C:\vikram\Project\Seurat\src\app\logitech\LogiRTP\Library\Filters\plc\common\bitstream.h(210) : see reference to function template instantiation 'void boost::to_block_range<uint8_t,std::allocator<_Ty>,bitstream::bitset_extractor<T>>(const boost::dynamic_bitset<Block> &,BlockOutputIterator)' being compiled
1>          with
1>          [
1>              _Ty=uint8_t,
1>              T=uint8_t,
1>              Block=uint8_t,
1>              BlockOutputIterator=bitstream::bitset_extractor<uint8_t>
1>          ]
1>C:\Program Files\Microsoft Visual Studio 10.0\VC\include\xutility(275): error C2582: 'operator =' function is unavailable in 'bitstream::bitset_extractor<T>'
1>          with
1>          [
1>              T=uint8_t
1>          ]

Answer 1

问题是您的bitset_extractor被用作迭代器，但它并不能满足迭代器的所有要求。

std::copy函数使用两个bitset_extractor<uint8_t>对象调用operator=，因为它试图将原始迭代器转换为检查迭代器。由于用户定义的迭代器不存在检查迭代器，所以检查迭代器类型和原始迭代器类型是相同的，因此将使用迭代器的常规副本。

罪魁祸首是_Rechecked函数，它用于将常规迭代器转换为检查迭代器。这是不同的操作，取决于迭代器调试级别；这就是为什么debug构建可以工作，而不是发行版构建，因为在默认情况下，它们有不同的迭代器调试级别。

解决方案是为operator=实现bitset_extractor。如果要将其用作迭代器，则必须支持其类型的迭代器所需的所有功能。

禁用检查过的迭代器不会有帮助。不管您做什么，迭代器仍将遍历_Rechecked函数。

Answer 2

解决了.I在VS项目设置->预处理器中添加了_SECURE_SCL=1的问题.

它很好用。