std::reference_wrapper

 

C++

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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)

 

Objetos Function

Envoltorios de función Original: Function wrappers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
function (C++11)
mem_fn (C++11)
bad_function_call (C++11)
Enlazar Original: Bind The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
bind (C++11)
is_bind_expression (C++11)
is_placeholder (C++11)
_1, _2, _3, ... (C++11)
Envolturas de referencia Original: Reference wrappers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
reference_wrapper (C++11)
ref cref (C++11) (C++11)
Envoltorios Operador Original: Operator wrappers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
plus minus negate multiplies divides modulus logical_and logical_or logical_not	equal_to not_equal_to greater less greater_equal less_equal bit_and bit_or bit_xor
Negadores Original: Negators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
unary_negate binary_negate	not1 not2
Desaprobado aglutinantes y adaptadores Original: Deprecated binders and adaptors The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
unary_function (obsoleto)
binary_function (obsoleto)
ptr_fun (obsoleto)
pointer_to_unary_function (obsoleto)
pointer_to_binary_function (obsoleto)
mem_fun (obsoleto)
mem_fun_t mem_fun1_t const_mem_fun_t const_mem_fun1_t (obsoleto) (obsoleto) (obsoleto) (obsoleto)
mem_fun_ref (obsoleto)
mem_fun_ref_t mem_fun1_ref_t const_mem_fun_ref_t const_mem_fun1_ref_t (obsoleto) (obsoleto) (obsoleto) (obsoleto)
binder1st binder2nd (obsoleto) (obsoleto)
bind1st bind2nd (obsoleto) (obsoleto)

 

std::reference_wrapper

Las funciones miembro Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

reference_wrapper::reference_wrapper

reference_wrapper::operator=

reference_wrapper::get reference_wrapper::operator T&

reference_wrapper::operator()

 

Defined in header <functional>
template< class T > class reference_wrapper;		(desde C++11)

std::reference_wrapper clase de plantilla es una CopyConstructible y la envoltura alrededor CopyAssignable una referencia al objeto o referencia a funcionar de T tipo. Las instancias de std::reference_wrapper son objetos (puede ser copiado o almacenado en contenedores), pero son implícitamente convertible a T&, de modo que puedan ser utilizados como argumentos con las funciones que toman el tipo subyacente por referencia .

Original:

Class template std::reference_wrapper is a CopyConstructible and CopyAssignable wrapper around a reference to object or reference to function of type T. Instances of std::reference_wrapper are objects (can be copied or stored in containers), but they are implicitly convertible to T&, so that they can be used as arguments with the functions that take the underlying type by reference.

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Las funciones de ayuda std::ref y std::cref se utilizan a menudo para generar std::reference_wrapper objetos .

Original:

Helper functions std::ref and std::cref are often used to generate std::reference_wrapper objects.

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std::reference_wrapper también se utiliza para pasar objetos a std::bind o al constructor de std::thread por referencia .

Original:

std::reference_wrapper is also used to pass objects to std::bind or to the constructor of std::thread by reference.

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Tipos de miembros

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
type	T
result_type	El tipo de retorno de T si T es una función. De lo contrario, no definida Original: The return type of T if T is a function. Otherwise, not defined The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
argument_type	1) si T es una función o un puntero a una función que toma un argumento de tipo A1, entonces argument_type es A1. 2) si T es un puntero a función miembro de clase T0 que no toma ningún argumento, entonces es argument_type T0*, posiblemente cv-qualified 3) si T es un tipo de clase con un T::argument_type tipo de miembro, entonces argument_type es un alias de eso Original: 1) if T is a function or pointer to function that takes one argument of type A1, then argument_type is A1. 2) if T is a pointer to member function of class T0 that takes no arguments, then argument_type is T0*, possibly cv-qualified 3) if T is a class type with a member type T::argument_type, then argument_type is an alias of that The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
first_argument_type	1) si T es una función o un puntero a una función que toma dos argumentos de tipo s A1 A2 y, a continuación, first_argument_type es A1. 2) si T es un puntero a función miembro de clase T0 que toma un argumento, entonces es first_argument_type T0*, posiblemente cv-qualified 3) si T es un tipo de clase con un T::first_argument_type tipo de miembro, entonces first_argument_type es un alias de eso Original: 1) if T is a function or pointer to function that takes two arguments of type s A1 and A2, then first_argument_type is A1. 2) if T is a pointer to member function of class T0 that takes one argument, then first_argument_type is T0*, possibly cv-qualified 3) if T is a class type with a member type T::first_argument_type, then first_argument_type is an alias of that The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
second_argument_type	1) si T es una función o un puntero a una función que toma dos argumentos de tipo s A1 A2 y, a continuación, second_argument_type es A2. 2) si T es un puntero a la función miembro de T0 clase que toma un argumento A1, entonces second_argument_type es A1, posiblemente cv-qualified 3) si T es un tipo de clase con un T::second_argument_type tipo de miembro, entonces first_argument_type es un alias de eso Original: 1) if T is a function or pointer to function that takes two arguments of type s A1 and A2, then second_argument_type is A2. 2) if T is a pointer to member function of class T0 that takes one argument A1, then second_argument_type is A1, possibly cv-qualified 3) if T is a class type with a member type T::second_argument_type, then first_argument_type is an alias of that The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Las funciones miembro

(constructor)	almacena una referencia a un objeto std::reference_wrapper nuevo Original: stores a reference in a new std::reference_wrapper object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (miembro público función)
operator=	vuelve a enlazar una std::reference_wrapper Original: rebinds a std::reference_wrapper The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (miembro público función)
get operator T&	accede a la referencia almacenada Original: accesses the stored reference The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (miembro público función)
operator()	llama a la función almacenada Original: calls the stored function The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (miembro público función)

Ejemplo

Muestra el uso de reference_wrapper como un contenedor de referencias, lo que hace posible acceder al mismo recipiente utilizando varios índices

Original:

Demonstrates the use of reference_wrapper as a container of references, which makes it possible to access the same container using multiple indexes

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#include <algorithm>
#include <list>
#include <vector>
#include <iostream>
#include <functional>
 
int main()
{
    std::list<int> l = {-4, -3, -2, -1, 0, 1, 2, 3, 4};
 
    std::vector<std::reference_wrapper<int>> v(l.begin(), l.end());
    std::random_shuffle(v.begin(), v.end());
 
    std::vector<std::reference_wrapper<int>> v2(v.begin(), v.end());
    std::partition(v2.begin(), v2.end(), [](int n){return n<0;});
 
    std::cout << "Contents of the list: ";
    for(int n: l) {
        std::cout << n << ' ';
    }
    std::cout << '\n';
 
    std::cout << "Contents of the list, shuffled: ";
    for(int i: v) {
        std::cout << i << ' ';
    }
    std::cout << '\n';
 
    std::cout << "Shuffled elements, partitioned: ";
    for(int i: v2) {
        std::cout << i << ' ';
    }
    std::cout << '\n';
}

Output:

Contents of the list: -4 -3 -2 -1 0 1 2 3 4 
Contents of the list, shuffled: 0 -1 3 4 -4 1 -2 -3 2 
Shuffled elements, partitioned: -3 -1 -2 -4 4 1 3 0 2

Ver también

ref cref (C++11) (C++11)	crea una std::reference_wrapper con un tipo de deducir de su argumento Original: creates a std::reference_wrapper with a type deduced from its argument The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (función de plantilla)
bind (C++11)	se une uno o más argumentos a un objeto de función Original: binds one or more arguments to a function object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (función de plantilla)