std::experimental::optional man page

std::experimental::optional< _Tp > — Class template for optional values.  

Synopsis

Inherits std::experimental::_Optional_base< _Tp >, and std::_Enable_copy_move< is_copy_constructible< _Tp >::value, __and_< is_copy_constructible< _Tp >, is_copy_assignable< _Tp > >::value, is_move_constructible< _Tp >::value, __and_< is_move_constructible< _Tp >, is_move_assignable< _Tp > >::value, optional< _Tp > >.

Public Types

using value_type = _Tp

Public Member Functions

template<typename _Up  = _Tp, enable_if_t< __and_< __not_< is_same< optional< _Tp >, decay_t< _Up >>>, is_constructible< _Tp, _Up &&>, is_convertible< _Up &&, _Tp > >::value, bool >  = true> constexpr optional (_Up &&__t)
template<typename _Up  = _Tp, enable_if_t< __and_< __not_< is_same< optional< _Tp >, decay_t< _Up >>>, is_constructible< _Tp, _Up &&>, __not_< is_convertible< _Up &&, _Tp >> >::value, bool >  = false> constexpr optional (_Up &&__t)
template<typename _Up , enable_if_t< __and_< __not_< is_same< _Tp, _Up >>, is_constructible< _Tp, const _Up &>, is_convertible< const _Up &, _Tp >, __not_< __converts_from_optional< _Tp, _Up >> >::value, bool >  = true> constexpr optional (const optional< _Up > &__t)
template<typename _Up , enable_if_t< __and_< __not_< is_same< _Tp, _Up >>, is_constructible< _Tp, const _Up &>, __not_< is_convertible< const _Up &, _Tp >>, __not_< __converts_from_optional< _Tp, _Up >> >::value, bool >  = false> constexpr optional (const optional< _Up > &__t)
template<typename _Up , enable_if_t< __and_< __not_< is_same< _Tp, _Up >>, is_constructible< _Tp, _Up &&>, is_convertible< _Up &&, _Tp >, __not_< __converts_from_optional< _Tp, _Up >> >::value, bool >  = true> constexpr optional (optional< _Up > &&__t)
template<typename _Up , enable_if_t< __and_< __not_< is_same< _Tp, _Up >>, is_constructible< _Tp, _Up &&>, __not_< is_convertible< _Up &&, _Tp >>, __not_< __converts_from_optional< _Tp, _Up >> >::value, bool >  = false> constexpr optional (optional< _Up > &&__t)
template<typename... _Args> enable_if_t< is_constructible< _Tp, _Args &&... >::value > emplace (_Args &&... __args)
template<typename _Up , typename... _Args> enable_if_t< is_constructible< _Tp, initializer_list< _Up > &, _Args &&... >::value > emplace (initializer_list< _Up > __il, _Args &&... __args)
constexpr operator bool () const noexcept
constexpr const _Tp & operator* () const &
constexpr _Tp & operator* () &
constexpr _Tp && operator* () &&
constexpr const _Tp && operator* () const &&
constexpr const _Tp * operator-> () const
_Tp * operator-> ()
optional & operator= (nullopt_t) noexcept
template<typename _Up  = _Tp> enable_if_t< __and_< __not_< is_same< optional< _Tp >, decay_t< _Up > > >, is_constructible< _Tp, _Up >, __not_< __and_< is_scalar< _Tp >, is_same< _Tp, decay_t< _Up > > > >, is_assignable< _Tp &, _Up > >::value, optional & > operator= (_Up &&__u)
template<typename _Up > enable_if_t< __and_< __not_< is_same< _Tp, _Up > >, is_constructible< _Tp, const _Up & >, is_assignable< _Tp &, _Up >, __not_< __converts_from_optional< _Tp, _Up > >, __not_< __assigns_from_optional< _Tp, _Up > > >::value, optional & > operator= (const optional< _Up > &__u)
template<typename _Up > enable_if_t< __and_< __not_< is_same< _Tp, _Up > >, is_constructible< _Tp, _Up >, is_assignable< _Tp &, _Up >, __not_< __converts_from_optional< _Tp, _Up > >, __not_< __assigns_from_optional< _Tp, _Up > > >::value, optional & > operator= (optional< _Up > &&__u)
void swap (optional &__other) noexcept(is_nothrow_move_constructible< _Tp >() &&noexcept(swap(declval< _Tp &>(), declval< _Tp &>())))
constexpr const _Tp & value () const &
constexpr _Tp & value () &
constexpr _Tp && value () &&
constexpr const _Tp && value () const &&
template<typename _Up > constexpr _Tp value_or (_Up &&__u) const &
template<typename _Up > _Tp value_or (_Up &&__u) &&

Private Member Functions

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 ()

Private Attributes

_Empty_byte _M_empty
_Stored_type _M_payload

Detailed Description

template<typename _Tp>

class std::experimental::optional< _Tp >" Class template for optional values.

Definition at line 83 of file optional.

Author

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Info

Thu May 4 2017 libstdc++