For the full specification, see section 6.3 of the C++ Standard Library Technical Report and issue 6.18 of the Library Extension Technical Report Issues List (page 63).

Defines boost::hash, and helper functions. std::unary_function<T, std::size_t> A TR1 compliant hash function object. std::size_t T const& hash_value(val) The call to hash_value is unqualified, so that custom overloads can be found via argument dependent lookup. This is not defined when the macro BOOST_HASH_NO_EXTENSIONS is defined. The specializations are still defined, so only the specializations required by TR1 are defined. Only throws if hash_value(T) throws. bool std::size_t bool Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw char std::size_t char Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw signed char std::size_t signed char Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw unsigned char std::size_t unsigned char Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw wchar_t std::size_t wchar_t Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw short std::size_t short Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw unsigned short std::size_t unsigned short Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw int std::size_t int Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw unsigned int std::size_t unsigned int Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw long std::size_t long Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw unsigned long std::size_t unsigned long Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw long long std::size_t long long Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw unsigned long long std::size_t unsigned long long Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw float std::size_t float Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw double std::size_t double Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw long double std::size_t long double Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw std::string std::size_t std::string const& Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw std::wstring std::size_t std::wstring const& Unspecified in TR1, except that equal arguments yield the same result. hash_value(val) in Boost. Doesn't throw T* std::size_t T* Unspecified in TR1, except that equal arguments yield the same result. Doesn't throw void size_t & T const& Called repeatedly to incrementally create a hash value from several variables. seed ^= hash_value(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2); hash_value is called without qualification, so that overloads can be found via ADL. This is an extension to TR1 Only throws if hash_value(T) throws. Strong exception safety, as long as hash_value(T) also has strong exception safety. std::size_t It It void std::size_t& It It Calculate the combined hash value of the elements of an iterator range. For the two argument overload: size_t seed = 0; for(; first != last; ++first) { hash_combine(seed, *first); } return seed; For the three arguments overload: for(; first != last; ++first) { hash_combine(seed, *first); } hash_range is sensitive to the order of the elements so it wouldn't be appropriate to use this with an unordered container. This is an extension to TR1 Only throws if hash_value(std::iterator_traits<It>::value_type) throws. hash_range(std::size_t&, It, It) has basic exception safety as long as hash_value(std::iterator_traits<It>::value_type) has basic exception safety. Implementation of the hash function. std::size_t bool std::size_t char std::size_t signed char std::size_t unsigned char std::size_t wchar_t std::size_t short std::size_t unsigned short std::size_t int std::size_t unsigned int std::size_t long std::size_t unsigned long std::size_t long long std::size_t unsigned long long std::size_t float std::size_t double std::size_t long double std::size_t T* const& std::size_t T (&val)[N] std::size_t const T (&val)[N] std::size_t std::basic_string<Ch, std::char_traits<Ch>, A> const& std::size_t std::pair<A, B> const& std::size_t std::vector<T, A> const& std::size_t std::list<T, A> const& std::size_t std::deque<T, A> const& std::size_t std::set<K, C, A> const& std::size_t std::multiset<K, C, A> const& std::size_t std::map<K, T, C, A> const& std::size_t std::multimap<K, T, C, A> const& std::size_t std::complex<T> const& Generally shouldn't be called directly by users, instead they should use boost::hash, boost::hash_range or boost::hash_combine which call hash_value without namespace qualification so that overloads for custom types are found via ADL. This is an extension to TR1 Only throws if a user supplied version of hash_value throws for an element of a container, or one of the types stored in a pair. Types Returns bool, char, signed char, unsigned char, wchar_t, short, unsigned short, int, unsigned int, long, unsigned long val long long, unsigned long long val when abs(val) <= std::numeric_limits<std::size_t>::max(). float, double, long double An unspecified value, except that equal arguments shall yield the same result. T* An unspecified value, except that equal arguments shall yield the same result. T val[N], const T val[N] hash_range(val, val+N) std:basic_string<Ch, std::char_traits<Ch>, A>, std::vector<T, A>, std::list<T, A>, std::deque<T, A>, std::set<K, C, A>, std::multiset<K, C, A>, std::map<K, T, C, A>, std::multimap<K, T, C, A> hash_range(val.begin(), val.end()) std::pair<A, B> size_t seed = 0; hash_combine(seed, val.first); hash_combine(seed, val.second); return seed; std::complex<T> When T is a built in type and val.imag() == 0, the result is equal to hash_value(val.real()). Otherwise an unspecified value, except that equal arguments shall yield the same result.