std::experimental::_Optional_base< _Tp, _ShouldProvideDestructor >

Section: C Library Functions (3)
Updated: Wed Apr 17 2019
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NAME

std::experimental::_Optional_base< _Tp, _ShouldProvideDestructor > - Class template that holds the necessary state for Optional values and that has the responsibility for construction and the special members.

SYNOPSIS

Public Member Functions

constexpr _Optional_base (nullopt_t) noexcept

template<typename... _Args> constexpr _Optional_base (in_place_t, _Args &&... __args)

template<typename _Up , typename... _Args, enable_if_t< is_constructible< _Tp, initializer_list< _Up > &, _Args &&... >::value, int > ...> constexpr _Optional_base (in_place_t, initializer_list< _Up > __il, _Args &&... __args)

_Optional_base (const _Optional_base &__other)

_Optional_base (_Optional_base &&__other) noexcept(is_nothrow_move_constructible< _Tp >())

_Optional_base & operator= (const _Optional_base &__other)

_Optional_base & operator= (_Optional_base &&__other) noexcept(__and_< is_nothrow_move_constructible< _Tp >, is_nothrow_move_assignable< _Tp >>())

Protected Member Functions

template<typename... _Args> void _M_construct (_Args &&... __args) noexcept(is_nothrow_constructible< _Stored_type, _Args... >())

void _M_destruct ()

constexpr _Tp & _M_get () noexcept

constexpr const _Tp & _M_get () const noexcept

constexpr bool _M_is_engaged () const noexcept

void _M_reset ()

Detailed Description

template<typename _Tp, bool _ShouldProvideDestructor = !is_trivially_destructible<_Tp>::value>

class std::experimental::_Optional_base< _Tp, _ShouldProvideDestructor >" Class template that holds the necessary state for Optional values and that has the responsibility for construction and the special members.

Such a separate base class template is necessary in order to conditionally enable the special members (e.g. copy/move constructors). Note that this means that _Optional_base implements the functionality for copy and move assignment, but not for converting assignment.

See also:

: optional, _Enable_special_members

Definition at line 202 of file optional.

Author

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