alignof operator (начиная с C++11)
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Запросы требования к выравниванию типа
Original:
Queries alignment requirements of a type
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Содержание |
[править] Синтаксис
alignof( type )
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Возвращает объект типа std::size_t.
Original:
Returns an object of type std::size_t.
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[править] Объяснение
Возвращает выравнивание в байтах (целое число степенью двойки), необходимых для любого экземпляра данного
type, который является либо полное тип, тип массива, или ссылки типа.Original:
Returns alignment in bytes (an integer power of two) required for any instance of the given
type, which is either complete type, an array type, or a reference type.The text has been machine-translated via Google Translate.
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Если тип является ссылочным типом, оператор возвращает выравнивание' ссылочного типа, если тип является типом массива, выравнивание требование тип элемента возвращается.
Original:
If the type is reference type, the operator returns the alignment of referenced type; if the type is array type, alignment requirement of the element type is returned.
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Типы char, signed char, и unsigned char имеют слабое (маленький) выравнивание поддерживается реализацией.
Original:
The types char, signed char, and unsigned char have the weakest (smallest) alignment supported by the implementation.
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[править] Ключевые слова
[править] Пример
#include <iostream> struct Empty {}; struct Foo { int f2; float f1; char c; }; int main() { std::cout << "alignment of empty class: " << alignof(Empty) << '\n' << "alignment of pointer : " << alignof(int*) << '\n' << "alignment of char : " << alignof(char) << '\n' << "alignment of Foo : " << alignof(Foo) << '\n' ; }
Вывод:
alignment of empty class: 1 alignment of pointer : 8 alignment of char : 1 alignment of Foo : 4
[править] См. также
| alignas спецификатор | указывает, что для хранения переменной должны быть согласованы конкретные (C++11) сумму
Original: specifies that the storage for the variable should be aligned by specific amount (C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| (C++11) |
получает выравнивания типа требований Original: obtains the type's alignment requirements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (шаблон класса) |
