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std::indirect<T, Allocator>:: valueless_after_move

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C++
Memory management library
( exposition only* )
Allocators
Uninitialized memory algorithms
Constrained uninitialized memory algorithms
Memory resources
Uninitialized storage (until C++20)
( until C++20* )
( until C++20* )
( until C++20* )

Garbage collector support (until C++23)
(C++11) (until C++23)
(C++11) (until C++23)
(C++11) (until C++23)
(C++11) (until C++23)
(C++11) (until C++23)
(C++11) (until C++23)
std::indirect
constexpr bool valueless_after_move ( ) const noexcept ;
(自 C++26 起)

检查 * this 是否为空值状态。

返回值

true 如果 * this 不包含有效值，否则为 false 。

示例

本节内容不完整
原因：缺少示例