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std:: remove_reference

From cppreference.net
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Compile-time rational arithmetic
Compile-time integer sequences
(C++14)
定义于头文件 <type_traits>
template < class T >
struct remove_reference ;
(C++11 起)

如果类型 T 是引用类型，则提供成员类型定义 type ，该类型为 T 所引用的类型。否则 type 为 T 。

如果程序为 std::remove_reference 添加特化，则行为未定义。

目录

成员类型

名称 定义
type T 所引用的类型，若 T 不是引用则返回 T 本身

辅助类型

template < class T >
using remove_reference_t = typename remove_reference < T > :: type ;
(C++14 起)

可能的实现 

template<class T> struct remove_reference { typedef T type; };
template<class T> struct remove_reference<T&> { typedef T type; };
template<class T> struct remove_reference<T&&> { typedef T type; };

示例

运行此代码 
#include <iostream>
#include <type_traits>
int main()
{
    std::cout << std::boolalpha;
    std::cout << "std::remove_reference<int>::type is int? "
              << std::is_same<int, std::remove_reference<int>::type>::value << '\n';
    std::cout << "std::remove_reference<int&>::type is int? "
              << std::is_same<int, std::remove_reference<int&>::type>::value << '\n';
    std::cout << "std::remove_reference<int&&>::type is int? "
              << std::is_same<int, std::remove_reference<int&&>::type>::value << '\n';
    std::cout << "std::remove_reference<const int&>::type is const int? "
              << std::is_same<const int,
                              std::remove_reference<const int&>::type>::value << '\n';
}

输出： 

std::remove_reference<int>::type is int? true
std::remove_reference<int&>::type is int? true
std::remove_reference<int&&>::type is int? true
std::remove_reference<const int&>::type is const int? true

参见

(C++11)
检查类型是否为 左值引用 或 右值引用
(类模板)
(C++11) (C++11)
为给定类型添加 左值 或 右值 引用
(类模板)
(C++20)
组合 std::remove_cv 与 std::remove_reference
(类模板)