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

 

C++

Lenguaje

Cabeceras

Conceptos

Biblioteca de utilidades

Biblioteca de cadenas

Biblioteca de contenedores

Biblioteca de algoritmos

Biblioteca de iteradores

Biblioteca numérica

Biblioteca de entrada/salida

Biblioteca de localización

Biblioteca de expresiones regulares (C++11)

Biblioteca de operaciones atómicas (C++11)

Biblioteca de hilos/subprocesos (C++11)

 

Utilidades de la biblioteca

Escriba apoyo (basic types, RTTI, type traits)

Gestión de memoria dinámica

Gestión de errores

Programa de servicios públicos

Funciones variadic

Fecha y hora

Objetos Function

initializer_list (C++11)

bitset

hash (C++11)

Operadores relacionales 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>=

Pares y tuplas 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)

Cambiar, hacia adelante y mover 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)

 

Escriba apoyo

Tipos básicos 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.
Tipos fundamentales
Tipos fijos ancho enteros (C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
Límites numéricos 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 numérico limita interfaz
Información de tipo en tiempo de ejecución 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
Caracteres de tipo 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.
Categorías primarias de tipo 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)

Propiedades de 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)

Operaciones compatibles 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_constructibleis_trivially_constructibleis_nothrow_constructible (C++11)(C++11)(C++11)
is_default_constructibleis_trivially_default_constructibleis_nothrow_default_constructible (C++11)(C++11)(C++11)
is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)
is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
is_destructibleis_trivially_destructibleis_nothrow_destructible (C++11)(C++11)(C++11)
has_virtual_destructor (C++11)
Relaciones y consultas de propiedad 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)
Modificaciones de tipo 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_cvremove_constremove_volatile (C++11)(C++11)(C++11) add_cvadd_constadd_volatile (C++11)(C++11)(C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_referenceadd_rvalue_reference (C++11)(C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
Transformaciones de tipo 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)
Escriba constantes rasgos 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)

 

Definido en la cabecera <type_traits>
template< class T, class U > struct is_assignable;	(1)	(desde C++11)
template< class T, class U > struct is_trivially_assignable;	(2)	(desde C++11)
template< class T, class U > struct is_nothrow_assignable;	(3)	(desde C++11)

1)

Si el std::declval<T>() = std::declval<U>() expresión está bien formado en su contexto sin evaluar, la proporciona el miembro constante value true iguales. Para cualquier otro tipo, es value 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)

lo mismo que 1), pero la evaluación de la expresión de asignación no llamar a cualquier operación que no es trivial .

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)

lo mismo que 1), pero la evaluación de la expresión de asignación no llamar a cualquier operación que no se 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 [estático]

true si T is assignable from U , false lo contrario 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. (miembro público estático constante)

Member functions

operator bool

convierte el objeto a bool, devuelve 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. (función miembro público)

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>

Ejemplo

#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';
}

Salida:

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

Ver también

is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)	Comprueba si un tipo tiene un operador de asignación de copia 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. (plantilla de clase)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)	Comprueba si un tipo tiene un operador de asignación movimiento 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. (plantilla de clase)