NAME¶

std::reference_wrapper::reference_wrapper - std::reference_wrapper::reference_wrapper

Synopsis¶

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

Constructs a new reference wrapper.

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

Parameters¶

x - an object to wrap
other - another reference wrapper

Exceptions¶

1)
noexcept specification:
noexcept(noexcept(FUN(std::declval<U>())))
where FUN is the set of imaginary functions described in the description above.

Example¶

This section is incomplete
Reason: no example

Defect reports

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

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