std::ref, std::cref

 

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)

 

Funzione oggetti

Funzione wrapper 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)
Associare 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)
Wrapper di riferimento 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)
Operatore wrapper 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
Negatori 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
Sconsigliata a leganti e adattatori 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 (deprecato)
binary_function (deprecato)
ptr_fun (deprecato)
pointer_to_unary_function (deprecato)
pointer_to_binary_function (deprecato)
mem_fun (deprecato)
mem_fun_t mem_fun1_t const_mem_fun_t const_mem_fun1_t (deprecato) (deprecato) (deprecato) (deprecato)
mem_fun_ref (deprecato)
mem_fun_ref_t mem_fun1_ref_t const_mem_fun_ref_t const_mem_fun1_ref_t (deprecato) (deprecato) (deprecato) (deprecato)
binder1st binder2nd (deprecato) (deprecato)
bind1st bind2nd (deprecato) (deprecato)

 

Elemento definito nell'header <functional>
template<class T > std::reference_wrapper<T> ref(T& t);	(1)	(dal C++11)
template<class T > std::reference_wrapper<T> ref(std::reference_wrapper<T> t );	(2)	(dal C++11)
template<class T > std::reference_wrapper<const T> cref(const T& t );	(3)	(dal C++11)
template<class T > std::reference_wrapper<const T> cref(std::reference_wrapper<T> t )	(4)	(dal C++11)

Modelli funzionali e refcref sono funzioni di supporto che generano un oggetto di tipo std::reference_wrapper, utilizzando l'argomento detrazione modello per determinare l'argomento modello del risultato.

Original:

Function templates ref and cref are helper functions that generate an object of type std::reference_wrapper, using template argument deduction to determine the template argument of the result.

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You can help to correct and verify the translation. Click here for instructions.

Parametri

t

-

lvalue riferimento all'oggetto che deve essere confezionate o un'istanza di std::reference_wrapper Original: lvalue reference to object that needs to be wrapped or an instance of 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.

Valore di ritorno

1) std::reference_wrapper<T>(t)

2) ref(t.get())

3) std::reference_wrapper<const T>(t)

4) cref(t.get())

Eccezioni fatte p

noexcept specification:  

noexcept

  (dal C++11)

Esempio

#include <functional>#include <iostream>   void f(int& n1, int& n2, constint& n3){std::cout<<"In function: "<< n1 <<' '<< n2 <<' '<< n3 <<'\n';++n1;// increments the copy of n1 stored in the function object++n2;// increments the main()'s n2// ++n3; // compile error}   int main(){int n1 =1, n2 =2, n3 =3;std::function<void()> bound_f =std::bind(f, n1, std::ref(n2), std::cref(n3)); n1 =10; n2 =11; n3 =12;std::cout<<"Before function: "<< n1 <<' '<< n2 <<' '<< n3 <<'\n'; bound_f();std::cout<<"After function: "<< n1 <<' '<< n2 <<' '<< n3 <<'\n';}

Output:

Before function: 10 11 12 In function: 1 11 12 After function: 10 12 12

Vedi anche

reference_wrapper (C++11)	CopyConstructible e CopyAssignable involucro di riferimento Original: CopyConstructible and CopyAssignable reference wrapper The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template)