Re: [Boost-users] unordered_map: user object as key

On 27 February 2010 19:37, André Santee wrote:

Thanks, I solved my problem by doing this:

namespace boost {     std::size_t hash_value(const GS_VECTOR2 &v2)     {         return ((std::size_t)v2.y*COLUMNS)+(std::size_t)v2.x;     } };

Is it also ok?

Yes, but unless you're using a really old compiler that doesn't support argument dependent lookup (ADL), you should put the function in the same namespace as your vector. You can read about ADL at: http://en.wikipedia.org/wiki/Argument_dependent_name_lookup Daniel