std::is_convertible

 

C++

言語

コンセプト

ユーティリティライブラリ

ストリングスライブラリ

コンテナライブラリ

アルゴリズムライブラリ

イテレータライブラリ

ニューメリックスライブラリ

入力/出力ライブラリ

ローカライゼーションライブラリ

正規表現ライブラリ (C++11)

アトミック操作ライブラリ (C++11)

スレッドのサポートライブラリ (C++11)

 

ユーティリティライブラリ

支援を入力します (basic types, RTTI, type traits)

動的なメモリ管理

エラー処理

プログラムユーティリティ

可変個引数関数

日付と時刻

関数オブジェクト

initializer_list (C++11)

bitset

hash (C++11)

関係演算子 Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

ペアとタプル Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

フォワード、スワップ、および移動 Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

支援を入力します

基本的なタイプ Original: Basic types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
基本的なタイプ
固定幅の整数型 (C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
数値の限界 Original: Numeric limits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
numeric_limits
Cの数値は、インターフェイスを制限します
実行時型情報 Original: Runtime type information The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
type_info type_index (C++11)	bad_typeid bad_cast
型の特徴 Original: Type traits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
プライマリタイプカテゴリ Original: Primary type categories The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_void (C++11) is_array (C++11) is_pointer (C++11) is_enum (C++11) is_union (C++11) is_class (C++11) is_function (C++11)	is_object (C++11) is_scalar (C++11) is_compound (C++11) is_integral (C++11) is_floating_point (C++11) is_fundamental (C++11) is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)

Typeプロパティ Original: Type properties The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_const (C++11) is_volatile (C++11) is_pod (C++11) is_empty (C++11) is_polymorphic (C++11) is_abstract (C++11)	is_trivial (C++11) is_trivially_copyable (C++11) is_standard_layout (C++11) is_literal_type (C++11) is_signed (C++11) is_unsigned (C++11)

サポートされる操作 Original: Supported operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_constructible is_trivially_constructible is_nothrow_constructible (C++11) (C++11) (C++11)
is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible (C++11) (C++11) (C++11)
is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)
is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)
is_destructible is_trivially_destructible is_nothrow_destructible (C++11) (C++11) (C++11)
has_virtual_destructor (C++11)
リレーションシップとプロパティクエリ Original: Relationships and property queries The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_same (C++11) is_base_of (C++11) is_convertible (C++11)	alignment_of (C++11) rank (C++11) extent (C++11)
型の変更 Original: Type modifications The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
remove_cv remove_const remove_volatile (C++11) (C++11) (C++11) add_cv add_const add_volatile (C++11) (C++11) (C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_reference add_rvalue_reference (C++11) (C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
型変換 Original: Type transformations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
aligned_storage (C++11) aligned_union (C++11) decay (C++11) enable_if (C++11)	conditional (C++11) common_type (C++11) underlying_type (C++11) result_of (C++11)
形質定数を入力します Original: Type trait constants The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
integral_constant (C++11)

 

Defined in header <type_traits>
template< class From, class To > struct is_convertible;		(C + + 11以来)

それはFromToを使用するように変換することができればタイプToの虚右辺がimplicit conversionを返す関数のreturn文で使用できる場合、つまり、、valueに一定true等しい部材を提供する。さもなければvalueですfalse.

Original:

If an imaginary rvalue of type From can used in the return statement of a function returning To, that is, if it can be converted to To using implicit conversion, provides the member constant value equal to true. Otherwise value is false.

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Inherited from std::integral_constant

Member constants

value [静的]	true From is convertible to To もし、そうでなければfalse Original: true if From is convertible to To , false otherwise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (公共の静的メンバ定数)

Member functions

operator bool	boolにオブジェクトは、value返しに変換します Original: converts the object to bool, returns value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (パブリックメンバ関数)

Member types

タイプ Original: Type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.	Definition
value_type	bool
type	std::integral_constant<bool, value>

ノート

参照型は、void型、配列型、関数型のための明確に定義された結果を与える.

Original:

Gives well-defined results for reference types, void types, array types, and function types.

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例

#include <iostream>
#include <type_traits>
 
int main() 
{
    class A {};
    class B: public A {};
    class C {};
 
    bool b2a = std::is_convertible<B*, A*>::value;
    bool a2b = std::is_convertible<A*, B*>::value;
    bool b2c = std::is_convertible<B*, C*>::value;
 
    std::cout << std::boolalpha;
    std::cout << b2a << '\n';
    std::cout << a2b << '\n';
    std::cout << b2c << '\n';
}

Output:

true
false
false