Struct template hash

boost::hash — A TR1 compliant hash function object.

Synopsis

// In header: <boost/functional/hash.hpp>

template<typename T> 
struct hash : public std::unary_function {
  std::size_t operator()(T const&) const;
};

Description

std::size_t operator()(T const& val) const;

Returns:

hash_value(val)

Notes:

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.

Forward declared in

This hash function is not intended for general use, and isn't guaranteed to be equal during separate runs of a program - so please don't use it for any persistent storage or communication.

Throws:

Only throws if hash_value(T) throws.

Boost C++ Libraries