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std::experimental::propagate_const<T>::propagate_const

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Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
 
 
 
constexpr propagate_const() = default;
(1) (library fundamentals TS v2)
constexpr propagate_const( propagate_const&& p ) = default;
(2) (library fundamentals TS v2)
template<class U>
/* see below */ constexpr propagate_const( propagate_const<U>&& pu );
(3) (library fundamentals TS v2)
template<class U>
/* see below */ constexpr propagate_const( U&& u );
(4) (library fundamentals TS v2)
propagate_const( const propagate_const& ) = delete;
(5) (library fundamentals TS v2)

Let t_ designate the private data member that is the wrapped pointer-like object.

1) Constructs an propagate_const, default-initializing this->t_.
2) Explicitly defaulted move constructor that move constructs this->t_ from p.t_.
3) Initializes this->t_ as if by direct-non-list-initialization from the expression std::move(pu.t_).
This constructor does not participate in overload resolution unless std::is_constructible<T, U>::value is true, and is explicit if and only if std::is_convertible<U, T>::value is false.
4) Initializes this->t_ as if by direct-non-list-initialization with the expression std::forward<U>(u).
This constructor does not participate in overload resolution unless std::is_constructible<T, U>::value is true and std::decay_t<U> is not a specialization of propagate_const. This constructor is explicit if and only if std::is_convertible<U, T>::value is false.
5) Copy constructor is explicitly deleted. propagate_const is non-copyable.

[edit] Parameters

p - another propagate_const object to move from
pu - another propagate_const object of a different specialization to move from
u - another object to initialize the contained pointer with

[edit] Notes

In Library Fundamental TS v2 (based on C++14), (4) and (5) are typically implemented in explicit/non-explicit overload pairs. Since Library Fundamental TS v3 (based on C++20), they can be implemented in conditional explicit specifiers.