相关疑难解决方法(0)

我在类层次结构中有一堆对象,并希望std::map使用对这些对象的引用作为映射中的键.它似乎std::reference_wrapper正是这需要的,但我似乎无法使它工作.到目前为止我尝试过的:

class Object { // base class of my hierarchy
    // most details unimportant
public
    virtual bool operator< (const Object &) const;  // comparison operator
};

std::map<std::reference_wrapper<const Object>, int> table;

auto it = table.find(object);

table[object] = 42;

table[object]++

但是,我总是从编译器中得到一些模糊的错误:

/usr/include/c++/4.5.3/bits/stl_function.h: In member function ‘bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = std::reference_wrapper<const Object>]’:
/usr/include/c++/4.5.3/bits/stl_tree.h:1522:38:   instantiated from ‘std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::find(const _Key&) [with _Key = std::reference_wrapper<const Object>, _Val = std::pair<const …