offsetof

 

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 <cstddef>
#define offsetof(type, member) /*implementation-defined*/

マクロoffsetofはstd::size_t型の定数に展開され、値が指定された型のオブジェクトの先頭から、もしあればパディングを含め、指定したメンバーに、バイト単位でオフセットされます.

Original:

The macro offsetof expands to a constant of type std::size_t, the value of which is the offset, in bytes, from the beginning of an object of specified type to its specified member, including padding if any.

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ノート

typeは、標準レイアウト型でない場合、動作は未定義です.

Original:

If type is not a standard-layout type, the behavior is undefined.

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memberは静的メンバあるいは関数メンバである場合、動作は未定義です.

Original:

If member is a static member or a function member, the behavior is undefined.

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標準レイアウトの種類の最初のメンバのオフセット（空のベース最適化必須です）は常にゼロです

Original:

The offset of the first member of a standard-layout type is always zero (空のベース最適化 is mandatory)

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可能な実装

#define offsetof(type,member) ((std::size_t) &(((type*)0)->member))

例

#include <iostream>
#include <cstddef>
struct S {
    char c;
    double d;
};
int main()
{
    std::cout << "the first element is at offset " << offsetof(S, c) << '\n'
              << "the double is at offset " << offsetof(S, d) << '\n';
}

Output:

the first element is at offset 0
the double is at offset 8

も参照してください

size_t	sizeof子によって戻された符号なし整数型 Original: unsigned integer type returned by the sizeof operator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (typedefです)
is_standard_layout (C++11)	タイプかどうかをチェックするには、標準レイアウトタイプです Original: checks if a type is standard-layout type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (クラステンプレート)