From cppreference.com
template<classT>structis_lvalue_reference;(since C++11)std::is_lvalue_reference is a
.
Checks whether T is an lvalue reference type. Provides the member constant value which is equal to true, if T is an lvalue reference type. Otherwise, value is equal to false.
If the program adds specializations for std::is_lvalue_reference or std::is_lvalue_reference_v, the behavior is undefined.
Template parameters
T - a type to check Helper variable template
template<classT>constexprboolis_lvalue_reference_v=is_lvalue_reference<T>::value;(since C++17)Inherited from
Member constants
value
[static]
true if T is an lvalue reference type, false otherwise
(public static member constant)Member functions
operator bool
converts the object to bool, returns value
(public member function)operator()
(C++14)
returns value
(public member function)Member types
Type Definition value_typebooltypestd::integral_constant<bool,value>Possible implementation
template<classT>structis_lvalue_reference:std::false_type{};template<classT>structis_lvalue_reference<T&>:std::true_type{};Example
Run this code
#include<type_traits>classA{};static_assert(std::is_lvalue_reference_v<A>==false);static_assert(std::is_lvalue_reference_v<A&>==true);static_assert(std::is_lvalue_reference_v<A&&>==false);static_assert(std::is_lvalue_reference_v<int>==false);static_assert(std::is_lvalue_reference_v<int&>==true);static_assert(std::is_lvalue_reference_v<int&&>==false);intmain(){}See also