<type_traits>

类模板
<type_traits>

std::add_pointer

template <class T> struct add_pointer;
Add pointer
Obtains the pointer type that points toT.

转换后的类型别名为成员类型add_pointer::type.

如果已知Tis a reference type, this isremove_reference<T>::type*, otherwise it isT*.

模板参数

T
一个类型。

成员类型

成员类型定义
类型如果已知Tis a reference typeremove_reference<T>::type*
否则T*

示例

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// add_pointer
#include <iostream>
#include <type_traits>

typedef std::add_pointer<int>::type A;        // int*
typedef std::add_pointer<const int>::type B;  // const int*
typedef std::add_pointer<int&>::type C;       // int*
typedef std::add_pointer<int*>::type D;       // int**
typedef std::add_pointer<int(int)>::type E;   // int(*)(int)


typedef int X[3];

int main() {
  std::cout << std::boolalpha;
  std::cout << "typedefs of int*:" << std::endl;
  std::cout << "A: " << std::is_same<int*,A>::value << std::endl;
  std::cout << "B: " << std::is_same<int*,B>::value << std::endl;
  std::cout << "C: " << std::is_same<int*,C>::value << std::endl;
  std::cout << "D: " << std::is_same<int*,D>::value << std::endl;
  std::cout << "E: " << std::is_same<int*,E>::value << std::endl;

  return 0;
}

输出
typedefs of int*:
A: true
B: false
C: true
D: false
E: false


另见