std::meta::is_pointer_interconvertible_base_of_type

 

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Scope identification current_function current_class current_namespace Reflection member queries members_of bases_of static_data_members_of nonstatic_data_members_of      subobjects_of enumerators_of Reflection layout queries offset_of size_of alignment_of bit_size_of Annotation reflection annotations_of annotations_of_with_type Value extraction extract Reflection substitution can_substitute substitute Expression result reflection reflect_constant reflect_object reflect_function Class definition generation data_member_spec is_data_member_spec define_aggregate

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Const-volatile modifications remove_const remove_volatile remove_cv add_const add_volatile add_cv Reference modifications remove_reference add_lvalue_reference add_rvalue_reference Sign modifications make_signed make_unsigned Array modifications remove_extent remove_all_extents Pointer modifications remove_pointer add_pointer Other transformations remove_cvref decay common_type common_reference underlying_type invoke_result unwrap_reference unwrap_ref_decay tuple_size tuple_element is_applicable_type is_nothrow_applicable_type apply_result variant_size variant_alternative type_order

 

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Defined in header <meta>
consteval bool is_pointer_interconvertible_base_of_type( std::meta::info base, std::meta::info derived );		(since C++26)

See More

Checks if reflected type Base (represented by base) is a pointer-interconvertible base of another type Derived (represented by derived).

If Derived is unambiguously derived from Base and every Derived object is pointer-interconvertible with its Base subobject, or if both are the same non-union class (in both cases ignoring cv-qualification), returns true. Otherwise returns false.

Equivalent to return std::is_pointer_interconvertible_base_of<Base, Derived>;.

If both Base and Derived are non-union class types, and they are not the same type (ignoring cv-qualification), Derived must be a complete type; otherwise the behavior is undefined.

Parameters

base, derived

-

reflection values to check

Return value

true if base represets a type that is pointer-interconvertible base of another type represented by derived, false otherwise.

Exceptions

Throws std::meta::exception if either base or derived does not represent a type or type alias.

Notes

std::is_pointer_interconvertible_base_of_v<T, U> may be true even if T is a private or protected base class of U.

Let

• U be a complete object type,
• T be a complete object type with cv-qualification not less than U,
• u be any valid lvalue of U,

reinterpret_cast<T&>(u) always has well-defined result if std::is_pointer_interconvertible_base_of_v<T, U> is true.

If T and U are not the same type (ignoring cv-qualification) and T is a pointer-interconvertible base class of U, then both std::is_standard_layout_v<T> and std::is_standard_layout_v<U> are true.

If T is standard layout class type, then all base classes of T (if any) are pointer-interconvertible base class of T.

Example

Run this code

#include <meta>

struct Foo {};

struct Bar {};

class Baz : Foo, public Bar { int x; };

class NonStdLayout : public Baz { int y; };

static_assert("all of:"
    and is_pointer_interconvertible_base_of_type(^^Bar, ^^Baz)
    and is_pointer_interconvertible_base_of_type(^^Foo, ^^Baz)
    and not is_pointer_interconvertible_base_of_type(^^Baz, ^^NonStdLayout)
    and is_pointer_interconvertible_base_of_type(^^NonStdLayout, ^^NonStdLayout)
);

int main() {}

See also

is_pointer_type (C++26)	checks if reflected type is a pointer type (function)
is_base_of_type (C++26)	checks if two reflections represent types such that one type is a base of the other type (function)
is_virtual_base_of_type (C++26)	checks if two reflections represent types such that one type is a virtual base of the other type (function)
is_standard_layout_type (C++26)	checks if reflected type is a standard-layout type (function)
is_convertible_typeis_nothrow_convertible_type (C++26)(C++26)	checks if reflected type can be converted to the other type (function)
is_empty_type (C++26)	checks if reflected type is a class (but not union) type and has no non-static data members (function)
is_pointer_interconvertible_base_of (C++20)	checks if a type is a pointer-interconvertible (initial) base of another type (class template)