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std::is_lvalue_reference

STD：：是[医]洛值[医]参照系

Defined in header ​​
template< class T > struct is_lvalue_reference;​(since C++11)

检查是否T是值引用类型。提供成员常量。value等于true，如果T是值引用类型。否则，value等于false...

模板参数

T-a type to check

辅助变量模板

template< class T > inline constexpr bool is_lvalue_reference_v = is_lvalue_reference::value;​(since C++17)

继承自STD：积分[医]常量

成员常数

value statictrue if T is an lvalue reference type , false otherwise (public static member constant)

成员函数

operator boolconverts the object to bool, returns value (public member function)
operator() (C++14)returns value (public member function)

成员类型

TypeDefinition
value_typebool
typestd::integral_constant<bool, value>

可能的实施

模板<class T>结构是[医]洛值[医]参考资料：std：：false[医]类型{}；模板<class T>结构是[医]洛值[医]参考<T&>：std：：true[医]{}型；

*。

例

二次

#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';
}

二次

产出：

二次

false
true
false
false
true
false

二次

另见

is_reference (C++11)checks if a type is either lvalue reference or rvalue reference (class template)
is_rvalue_reference (C++11)checks if a type is rvalue reference (class template)

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