std::is_lvalue_reference - cppreference.com (original) (raw)
| | | | | -------------------------------------------------- | | ------------- | | template< class T > struct is_lvalue_reference; | | (since C++11) |
std::is_lvalue_reference is a UnaryTypeTrait.
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.
Contents
[edit] Template parameters
[edit] Helper variable template
| template< class T > constexpr bool is_lvalue_reference_v = is_lvalue_reference<T>::value; | | (since C++17) | | ------------------------------------------------------------------------------------------------- | | ------------- |
Inherited from std::integral_constant
Member constants
| | true if T is an lvalue reference type, false otherwise (public static member constant) | | ----------------------------------------------------------------------------------------- |
Member functions
| | converts the object to bool, returns value (public member function) | | ---------------------------------------------------------------------- | | | returns value (public member function) |
Member types
[edit] Possible implementation
[edit] Example
#include class A {}; static_assert(std::is_lvalue_reference_v == 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 == false); static_assert(std::is_lvalue_reference_v<int&> == true); static_assert(std::is_lvalue_reference_v<int&&> == false); int main() {}