std::is_copy_assignable, std::is_trivially_copy_assignable, std::is_nothrow_copy_assignable

 

C++

Linguaggio

Concetti

Libreria di Utilità

Stringhe

Contenitori

Algoritmi

Iteratori

Libreria matematca

Input/output

Localizzazione

Espressioni regolari(C++11)

Operazioni atomicche(C++11)

Multithreading(C++11)

 

Utilità libreria

Tipo di supporto (basic types, RTTI, type traits)

Gestione della memoria dinamica

La gestione degli errori

Programma di utilità

Funzioni variadic

Data e ora

Funzione oggetti

initializer_list (C++11)

bitset

hash (C++11)

Gli operatori relazionali 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>=

Coppie e tuple 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)

Swap, in avanti e spostare 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)

 

Tipo di supporto

Tipi 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.
Tipi fondamentali
Larghezza fissa interi tipi(C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
Limiti numerici 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 numerico limita interfaccia
Informazioni sul tipo di runtime 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
Tipo tratti 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.
Categorie di tipo primario 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)

Proprietà del tipo 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)

Operazioni supportate 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)
I rapporti e le query di proprietà 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)
Tipo modifiche 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)
Tipo di trasformazioni 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)
Digitare costanti tratto 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)

 

Elemento definito nell'header <type_traits>
template<class T > struct is_copy_assignable;	(1)	(dal C++11)
template<class T > struct is_trivially_copy_assignable;	(2)	(dal C++11)
template<class T > struct is_nothrow_copy_assignable;	(3)	(dal C++11)

1)

Verifica se un tipo è CopyAssignable, cioè ha un accesso esplicito o implicito operatore di assegnamento per copia. Se la condizione è soddisfatta, un membro costante valuetrue parità è previsto, in caso contrario è valuefalse.

Original:

Checks whether a type is CopyAssignable, i.e. has an accessible explicit or implicit copy assignment operator. If the requirement is met, a member constant value equal true is provided, otherwise value is false.

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2)

Come 1), ma la valutazione della copia-assegnazione espressione non chiamerà qualsiasi operazione che non è banale.

Original:

Same as 1), but evaluation of the copy-assignment expression will not call any operation that is not trivial.

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3)

Uguale a 1), ma la valutazione della copia-assegnazione espressione non chiamerà qualsiasi operazione che non è noexcept.

Original:

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

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Inherited from std::integral_constant

Member constants

value [statico]	true se T is copy-assignable, false altrimenti Original: true if T is copy-assignable, false otherwise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (pubblico membro statico costante)

Member functions

operator bool	converte l'oggetto in bool, restituisce 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. (metodo pubblico)

Member types

Tipo 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>

Possibile implementazione

template<class T>struct is_copy_assignable :std::is_assignable<typenamestd::add_lvalue_reference<T>::type, consttypenamestd::add_lvalue_reference<T>::type>{};   template<class T>struct is_trivially_copy_assignable :std::is_trivially_assignable<typenamestd::add_lvalue_reference<T>::type, consttypenamestd::add_lvalue_reference<T>::type>{};   template<class T>struct is_nothrow_copy_assignable :std::is_nothrow_assignable<typenamestd::add_lvalue_reference<T>::type, consttypenamestd::add_lvalue_reference<T>::type>{};

Esempio

#include <iostream>#include <utility>#include <type_traits>struct Foo {int n;};int main(){std::cout<<std::boolalpha<<"Foo is trivally copy-assignable? "<< std::is_trivially_copy_assignable<Foo>::value<<'\n'<<"int[2] is copy-assignable? "<< std::is_copy_assignable<int[2]>::value<<'\n'<<"int is nothrow copy-assignable? "<< std::is_nothrow_copy_assignable<int>::value<<'\n';}

Output:

Foo is trivally copy-assignable? true int[2] is copy-assignable? false int is nothrow copy-assignable? true

Vedi anche

is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)	Verifica se un tipo ha un operatore di assegnazione per un argomento specifico Original: checks if a type has a assignment operator for a specific argument The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)	Verifica se un tipo ha un operatore di assegnamento mossa 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 template)