std::experimental::propagate_const<T>::propagate_const
From cppreference.com
constexpr propagate_const() = default;
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(1) | (library fundamentals TS v2) |
constexpr propagate_const( propagate_const&& p ) = default;
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(2) | (library fundamentals TS v2) |
template< class U >
/* see below */ constexpr propagate_const( propagate_const<U>&& pu );
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(3) | (library fundamentals TS v2) |
template< class U >
/* see below */ constexpr propagate_const( U&& u );
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(4) | (library fundamentals TS v2) |
propagate_const( const propagate_const& ) = delete;
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(5) | (library fundamentals TS v2) |
Let t_ designate the private data member that is the wrapped pointer-like object.
1) Constructs a
propagate_const, default-initializing this->t_.2) Explicitly defaulted move constructor that move constructs
this->t_ from p.t_.3) Initializes
This constructor does not participate in overload resolution unless
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 constructor does not participate in overload resolution unless
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.Parameters
| p | - | another propagate_const object to move from
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| pu | - | another propagate_const object of a different specialization to move from
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| u | - | another object to initialize the contained pointer with |
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.