Named requirements: ProFacade

A type F meets the ProFacade requirements of a type P if F meets the ProBasicFacade requirements, and the following expressions are well-formed and have the specified semantics.

Expressions	Semantics
typename F::convention_types	A tuple-like type that contains any number of distinct types Cs. Each type C in Cs shall meet the ProConvention requirements of P.
typename F::reflection_types	A tuple-like type that contains any number of distinct types Rs. Each type R in Rs shall meet the ProReflection requirements of P.
F::max_size	A core constant expression of type std::size_t that shall be greater than or equal to sizeof(P).
F::max_align	A core constant expression of type std::size_t that shall be greater than or equal to alignof(P).
F::copyability	A core constant expression of type constraint_level that defines the required copyability of P.
F::relocatability	A core constant expression of type constraint_level that defines the required relocatability of P.
F::destructibility	A core constant expression of type constraint_level that defines the required destructibility of P.

Since 4.0.2: P shall be a pointer-like type eligible for proxy. A type P is eligible if the following condition is satisfied:

(std::is_pointer_v<T> || requires { typename T::element_type; } || requires(T val) { *val; }) && requires { typename std::pointer_traits<T>::element_type; }

In other words, P either supports dereferencing or provides an element_type, and std::pointer_traits<P> yields a valid element_type.

Notes

Relocatability is defined as move-construct an object and then destroy the original instance. Specifically, the value of F::relocatability maps to the following requirements on P:

Value	Requirement on P
constraint_level::none	None
constraint_level::nontrivial	(std::is_move_constructible_v<P> && std::is_destructible_v<P>) ||is_bitwise_trivially_relocatable_v<P>
constraint_level::nothrow	(std::is_nothrow_move_constructible_v<P> && std::is_nothrow_destructible_v<P>) ||is_bitwise_trivially_relocatable_v<P>
constraint_level::trivial	is_bitwise_trivially_relocatable_v<P>

See Also

• concept proxiable
• ProBasicFacade requirements