#include <functional_hash.h>

Inheritance diagram for std::__is_fast_hash< _Hash >:

Public Types
typedef integral_constant< _Tp, __v >	type

typedef _Tp	value_type

Public Member Functions
constexpr	operator value_type () const noexcept

constexpr value_type	operator() () const noexcept

Static Public Attributes
static constexpr _Tp	value

Detailed Description

template<typename _Hash>
struct std::__is_fast_hash< _Hash >

Hint about performance of hash functions.

If a given hash function object is not fast, the hash-based containers will cache the hash code. The default behavior is to consider that hashers are fast unless specified otherwise.

Users can specialize this for their own hash functions in order to force caching of hash codes in unordered containers. Specializing this trait affects the ABI of the unordered containers, so use it carefully.

Definition at line 295 of file functional_hash.h.