std::is_lvalue_reference
From cppreference.com
Defined in header
<type_traits>
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||
template< class T >
struct is_lvalue_reference; |
(since C++11) | |
Checks whether T
is a lvalue reference type. Provides the member constant value
which is equal to true, if T
is a lvalue reference type. Otherwise, value
is equal to false.
Contents |
[edit] Template parameters
T | - | a type to check |
Inherited from std::integral_constant
Member constants
value
[static]
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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)
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returns value (public member function) |
Member types
Type | Definition |
value_type
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bool
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type
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std::integral_constant<bool, value> |
[edit] Possible implementation
template<class T> struct is_lvalue_reference : std::false_type {}; template<class T> struct is_lvalue_reference<T&> : std::true_type {}; |
[edit] Example
Run this code
#include <iostream> #include <type_traits> class A {}; int main() { std::cout << std::boolalpha; std::cout << std::is_lvalue_reference<A>::value << '\n'; std::cout << std::is_lvalue_reference<A&>::value << '\n'; std::cout << std::is_lvalue_reference<A&&>::value << '\n'; std::cout << std::is_lvalue_reference<int>::value << '\n'; std::cout << std::is_lvalue_reference<int&>::value << '\n'; std::cout << std::is_lvalue_reference<int&&>::value << '\n'; }
Output:
false true false false true false
[edit] See also
(C++11)
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checks if a type is either lvalue reference or rvalue reference (class template) |
(C++11)
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checks if a type is rvalue reference (class template) |
(library fundamentals TS)
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variable template alias of std::is_lvalue_reference::value (variable template) |