Editing Reference (C++) (section)

=== Rvalue reference ===
The declaration of the form:

 <Type>&& <Name>

where <code><Type></code> is a type and <code><Name></code> is an identifier is said to define an identifier whose type is '''[[rvalue reference]] to <code><Type></code>'''. 
Since the name of an [[Value (computer science)#lrvalue|rvalue]] reference is itself an lvalue, <code>std::move</code> must be used to pass an rvalue reference to a function overload accepting an rvalue reference parameter. Rvalue references to cv-unqualified type template parameters of that same function template or <code>auto&&</code> except when deduced from a brace-enclosed initializer list are called '''forwarding references''' (referred to as "universal references" in some older sources<ref>{{cite web|url=http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4164.pdf|title=Forwarding References|last1=Sutter|first1=Herb|last2=Stroustrup|first2=Bjarne|last3=Dos Reis|first3=Gabriel}}</ref>) and can act as lvalue or rvalue references depending on what is passed to them.<ref>[[#cpp-std|ISO/IEC 14822]], clause 13.10.2.1, paragraph 3.</ref>
When found in function parameters, they are sometimes used with <code>std::forward</code> to forward the function argument to another function while preserving the value category (lvalue or rvalue) it had when passed to the calling function.<ref>{{cite web|url=http://thbecker.net/articles/rvalue_references/section_01.html|title=C++ Rvalue References Explained|last=Becker|first=Thomas|accessdate=2022-11-25}}</ref>

Types which are of kind "reference to <code><Type></code>" are sometimes called '''reference types'''. Identifiers which are of reference type are called '''reference variables'''. To call them ''variable'', however, is in fact a misnomer, as we will see.