c++ - boost::uuids::uuid as a key in std::unordered_map? -


i'm using clang (cxx='clang++ -std=c++11 -stdlib=libc++') on mac os x, boost 1.53.0.

i want use uuid keys in unordered_map, getting following errors:

/usr/bin/../lib/c++/v1/type_traits:748:38: error: implicit instantiation of undefined template       'std::__1::hash<boost::uuids::uuid>'     : public integral_constant<bool, __is_empty(_tp)> {};                                  ^ /usr/bin/../lib/c++/v1/unordered_map:327:54: note: in instantiation of template class       'std::__1::is_empty<std::__1::hash<boost::uuids::uuid> >' requested here template <class _key, class _tp, class _hash, bool = is_empty<_hash>::value

...

/usr/bin/../lib/c++/v1/unordered_map:327:71: error: no member named 'value' in       'std::__1::is_empty<std::__1::hash<boost::uuids::uuid> >' template <class _key, class _tp, class _hash, bool = is_empty<_hash>::value                                                      ~~~~~~~~~~~~~~~~~^

...

what - bug in boost, makes incompatible c++ lib? or doing wrong? workarounds?

why bug in boost? should specialize std::hash template boost::uuid.

#include <boost/functional/hash.hpp>  namespace std {  template<> struct hash<boost::uuids::uuid> {     size_t operator () (const boost::uuids::uuid& uid)     {         return boost::hash<boost::uuids::uuid>()(uid);     } };  }

or, create unordered_map boost::hash par

std::unordered_map<boost::uuids::uuid, t, boost::hash<boost::uuids::uuid>>

or provide hash functor satisfies requirements of std::hash (thanks praetorian).


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