std::reference_wrapper<T>:: reference_wrapper

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Partial function application
bind_front bind_back (C++20) (C++23)
bind (C++11)
is_bind_expression (C++11)
is_placeholder (C++11)
_1, _2, _3, ... (C++11)

Reference wrappers
reference_wrapper (C++11)
ref cref (C++11) (C++11)
unwrap_reference unwrap_ref_decay (C++20) (C++20)

Negators
not_fn (C++17)
Searchers
default_searcher (C++17)
boyer_moore_searcher (C++17)
boyer_moore_horspool_searcher (C++17)

unary_function ( until C++17* )
binary_function ( until C++17* )
ptr_fun ( until C++17* )
pointer_to_unary_function ( until C++17* )
pointer_to_binary_function ( until C++17* )
mem_fun ( until C++17* )
mem_fun_t mem_fun1_t const_mem_fun_t const_mem_fun1_t ( until C++17* ) ( until C++17* ) ( until C++17* ) ( until C++17* )
not1 ( until C++20* )
not2 ( until C++20* )

binder1st binder2nd ( until C++17* ) ( until C++17* )
bind1st bind2nd ( until C++17* ) ( until C++17* )

mem_fun_ref ( until C++17* )
mem_fun_ref_t mem_fun1_ref_t const_mem_fun_ref_t const_mem_fun1_ref_t ( until C++17* ) ( until C++17* ) ( until C++17* ) ( until C++17* )
unary_negate ( until C++20* )
binary_negate ( until C++20* )

template < class U > reference_wrapper ( U && x ) noexcept ( /see below/ ) ;	(1)	(since C++11) (constexpr since C++20)
reference_wrapper ( const reference_wrapper & other ) noexcept ;	(2)	(since C++11) (constexpr since C++20)

Constructs a new reference wrapper.

1) Converts x to

T&

as if by T & t = std:: forward < U > ( x ) ; , then stores a reference to

. This overload participates in overload resolution only if typename std:: decay < U > :: type is not the same type as


        reference_wrapper

and the expression FUN ( std:: declval < U > ( ) ) is well-formed, where

FUN

names the set of imaginary functions

void FUN(T&) noexcept;
void FUN(T&&) = delete;

2) Copy constructor. Stores a reference to other. get ( ) .

x	-	an object to wrap
other	-	another reference wrapper

noexcept ( noexcept ( FUN ( std:: declval < U > ( ) ) ) )

where

FUN

is the set of imaginary functions described in the description above.

This section is incomplete
Reason: no example

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 2993	C++11	deleted `reference_wrapper(T&&)` constructor interferes with overload resolution in some cases	replaced with a constructor template

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External libraries

Member functions
reference_wrapper::reference_wrapper
reference_wrapper::operator=
reference_wrapper::get reference_wrapper::operator T&
reference_wrapper::operator()
Non-member functions
operator== operator<=> (C++26) (C++26)
Deduction guides (C++17)
Helper classes
basic_common_reference <std::reference_wrapper> (C++23)