std::expected<T,E>::error

 

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std::expected

成員函式

expected::expected

expected::~expected

expected::operator=

觀察器

expected::operator->expected::operator*

expected::operator boolexpected::has_value

expected::value

expected::error

expected::value_or

expected::error_or

Monadic operations

expected::and_then

expected::or_else

expected::transform

expected::transform_error

修改器

expected::emplace

expected::swap

非成員函式

operator==(std::expected)

swap(std::expected)

輔助類

unexpected

bad_expected_access

unexpect_tunexpect

 

constexpr const E& error() const& noexcept;	(1)	(C++23 起)
constexpr E& error() & noexcept;	(2)	(C++23 起)
constexpr const E&& error() const&& noexcept;	(3)	(C++23 起)
constexpr E&& error() && noexcept;	(4)	(C++23 起)

訪問 *this 中包含的意外值。

如果 has_value() 為 true，則行為未定義。

返回值

1,2) unex

3,4) std::move(unex)

參閱

error_or	如果存在則返回意外值，否則返回另一個值 (public member function)
operator->operator*	訪問預期值 (public member function)
value	返回預期值 (public member function)
operator boolhas_value	檢查物件是否包含預期值 (public member function)