std::is_copy_constructible, std::is_trivially_copy_constructible, std::is_nothrow_copy_constructible
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Déclaré dans l'en-tête <type_traits>
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template< class T > struct is_copy_constructible; |
(1) | (depuis C++11) |
template< class T > struct is_trivially_copy_constructible; |
(2) | (depuis C++11) |
template< class T > struct is_nothrow_copy_constructible; |
(3) | (depuis C++11) |
Vérifie si un type est
2) CopyConstructible
, c'est à dire a un constructeur de copie accessible explicite ou implicite. Si la condition est remplie, le membre constant value
égal à true est fourni, sinon value
vaut false .Original:
Checks whether a type is
CopyConstructible
, i.e. has an accessible explicit or implicit copy constructor. If the requirement is met, a member constant value
equal true is provided, otherwise value
is false.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Idem (1), mais l'expression constructeur de copie ne remet pas une opération qui n'est pas anodin .
3) Original:
Same as (1), but the copy constructor expression does not call any operation that is not trivial.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Idem (1), mais l'expression constructeur de copie est noexcept .
Original:
Same as (1), but the copy constructor expression is noexcept.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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Sommaire |
Inherited from std::integral_constant
Member constants
value [ statique ]Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
true si T is copy-constructible , false autrement Original: true if T is copy-constructible , false otherwise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) |
Member functions
operator bool |
convertit l'objet en bool, retourne value 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. (fonction membre publique) |
Member types
Type d'
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
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bool
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type
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std::integral_constant<bool, value> |
[modifier] Mise en œuvre possible
template<class T> struct is_copy_constructible : std::is_constructible<T, const typename std::add_lvalue_reference<T>::type> {}; template<class T> struct is_trivially_copy_constructible : std::is_trivially_constructible<T, const typename std::add_lvalue_reference<T>::type> {}; template<class T> struct is_nothrow_copy_constructible : std::is_nothrow_constructible<T, const typename std::add_lvalue_reference<T>::type> {}; |
[modifier] Exemple
#include <iostream> #include <type_traits> struct Ex1 { std::string str; // member has a non-trivial copy ctor }; struct Ex2 { int n; Ex2(const Ex2&) = default; // trivial and non-throwing }; int main() { std::cout << std::boolalpha << "Ex1 is copy-constructible? " << std::is_copy_constructible<Ex1>::value << '\n' << "Ex1 is trivially copy-constructible? " << std::is_trivially_copy_constructible<Ex1>::value << '\n' << "Ex2 is trivially copy-constructible? " << std::is_trivially_copy_constructible<Ex2>::value << '\n' << "Ex2 is nothrow copy-constructible? " << std::is_nothrow_copy_constructible<Ex2>::value << '\n'; }
Résultat :
Ex1 is copy-constructible? true Ex1 is trivially copy-constructible? false Ex2 is trivially copy-constructible? true Ex2 is nothrow copy-constructible? true
[modifier] Voir aussi
(C++11) (C++11) (C++11) |
vérifie si un type a un constructeur pour les arguments spécifiques Original: checks if a type has a constructor for specific arguments The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique) |
(C++11) (C++11) (C++11) |
vérifie si un type a un constructeur par défaut Original: checks if a type has a default constructor The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique) |
(C++11) (C++11) (C++11) |
vérifie si un type a un constructeur déménagement Original: checks if a type has a move constructor The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique) |