std::__is_fast_hash - Man Page

std::__is_fast_hash< _Hash >

Synopsis

#include <functional>

Inherits std::integral_constant< _Tp, __v >.

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.

Member Typedef Documentation

template<typename _Tp , _Tp __v> typedef integral_constant<_Tp, __v> std::integral_constant< _Tp, __v >::type [inherited]

Definition at line 66 of file type_traits.

template<typename _Tp , _Tp __v> typedef _Tp std::integral_constant< _Tp, __v >::value_type [inherited]

Definition at line 65 of file type_traits.

Member Function Documentation

template<typename _Tp , _Tp __v> constexpr std::integral_constant< _Tp, __v >::operator value_type () const [inline], [constexpr], [noexcept], [inherited]

Definition at line 67 of file type_traits.

template<typename _Tp , _Tp __v> constexpr value_type std::integral_constant< _Tp, __v >::operator() () const [inline], [constexpr], [noexcept], [inherited]

Definition at line 72 of file type_traits.

Member Data Documentation

template<typename _Tp , _Tp __v> constexpr _Tp std::integral_constant< _Tp, __v >::value [static], [constexpr], [inherited]

Definition at line 64 of file type_traits.

Author

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Info

Thu Jan 19 2023 libstdc++