std::is_assignable, std::is_trivially_assignable, std::is_nothrow_assignable

 

C++

Langage

Concepts

Bibliothèque d'utilitaires

Bibliothèque pour les chaînes de caractères

Bibliothèque de conteneurs

Bibliothèque d'algorithmes

Bibliothèque d'itérateurs

Bibliothèque pour le calcul numérique

Bibliothèque pour les entrées/sorties

Bibliothèque pour la régionalisation

Bibliothèque pour les expressions régulières (C++11)

Bibliothèque pour les opérations atomiques (C++11)

Bibliothèque pour les processus légers (threads) (C++11)

 

Bibliothèque d'utilitaires

Soutien des types fondamentaux (basic types, RTTI, type traits)

Gestion dynamique de la mémoire

Gestion d'erreur

Soutien à l'exécution

Fonctions variadic

Date et heure

Foncteurs

initializer_list (C++11)

bitset

hash (C++11)

Opérateurs relationnels

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

Paires et tuples

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

swap, forward et move

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

Soutien aux types fondamentaux

Les types de base 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.
Types fondamentaux
Fixe les types entiers largeur (C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
Limites numériques 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 numérique limite interface
Informations sur le type d'exécution 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
Caractères de type 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.
Catégories de type primaire 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)

Les propriétés du type 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)

Opérations prises en charge 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)
Les relations et les requêtes de propriété 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)
Modifications de type 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)
Transformations de type 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)
Tapez constantes traits 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)

 

Déclaré dans l'en-tête <type_traits>
template<class T, class U > struct is_assignable;	(1)	(depuis C++11)
template<class T, class U > struct is_trivially_assignable;	(2)	(depuis C++11)
template<class T, class U > struct is_nothrow_assignable;	(3)	(depuis C++11)

1)

Si le std::declval<T>()=std::declval<U>() expression est bien formée dans un contexte non évaluée, donne du membre de constante valuetrue égale. Pour tout autre type, value est false .

Original:

If the expression std::declval<T>()=std::declval<U>() is well-formed in unevaluated context, provides the member constant value equal true. For any other type, 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.

2)

même que 1), mais l'évaluation de l'expression d'affectation ne sera pas appeler toute opération qui n'est pas anodin .

Original:

same as 1), but evaluation of the assignment expression will 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.

3)

même que 1), mais l'évaluation de l'expression d'affectation ne sera pas appeler toute opération qui n'est pas noexcept .

Original:

same as 1), but the evaluation of the assignment expression will not call any operation that is not noexcept.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

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 assignable from U , false autrement Original: true if T is assignable from U , 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	bool
type	std::integral_constant<bool, value>

Exemple

#include <iostream>#include <string>#include <type_traits>struct Ex1 {int n;};int main(){std::cout<<std::boolalpha<<"int is assignable from double? "<< std::is_assignable<int, double>::value<<'\n'<<"int& is nothrow assignable from double? "<< std::is_nothrow_assignable<int&, double>::value<<'\n'<<"string is assignable from double? "<< std::is_assignable<std::string, double>::value<<'\n'<<"Ex1& is trivially assignable from const Ex1&? "<< std::is_trivially_assignable<Ex1&, const Ex1&>::value<<'\n';}

Résultat :

int is assignable from double? false int& is nothrow assignable from double? true string is assignable from double? true Ex1& is trivially assignable from const Ex1&? true

Voir aussi

is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)	vérifie si un type a un opérateur d'affectation de copie Original: checks if a type has a copy assignment operator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)	vérifie si un type a un opérateur d'affectation mouvement Original: checks if a type has a move assignment operator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique)