std::size_t hash_value(float val);
std::size_t hash_value(double val);
std::size_t hash_value(long double val);

Description

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.

Notes: Overloads for other types supplied in other headers.

This is an extension to TR1

Returns: An unspecified value, except that equal arguments shall yield the same result