template<typename A, typename B> 
  std::size_t hash_value(std::pair<A, B> const & val);

Description

Effects:

size_t seed = 0;
hash_combine(seed, val.first);
hash_combine(seed, val.second);
return seed;
        

Throws: Only throws if hash_value(A) or hash_value(B) throws.
Notes: This is an extension to TR1