std::addressof

来自cppreference.com
< cpp‎ | memory

 
 
 
 
定义于头文件 <memory>
template< class T >
T* addressof(T& arg);
(C++11 起)

Obtains the actual address of the object or function arg, even in presence of overloaded operator&

目录

[编辑] 参数

arg - lvalue object or function

[编辑] 返回值

Pointer to arg.

[编辑] 例外

noexcept规定:  
noexcept
  (C++11 起)

[编辑] 可能的实现

template< class T >
T* addressof(T& arg) {
    return (T*)&(char&)arg;
}

[编辑] 示例

operator& may be overloaded for a pointer wrapper class to obtain a pointer to pointer:

#include <iostream>
#include <memory>
 
template<class T>
struct Ptr {
   T* data;
   Ptr(T* arg) : data(arg) {}
   ~Ptr() {delete data;}
   T** operator&() { return &data; }
};
 
template<class T>
void f(Ptr<T>* p) {
    std::cout << "Ptr overload called with p = " << p << '\n';
}
 
void f(int** p) {
    std::cout << "int** overload called with p = " << p << '\n';
}
 
int main()
{
    Ptr<int> p(new int(42));
    f(&p);                 // calls int** overload
    f(std::addressof(p));  // calls Ptr<int>* overload
}

输出:

int** overload called with p = 0012FF64
Ptr overload called with p = 0012FF64

[编辑] 另请参阅

默认的分配器
(类模板) [编辑]
提供有关类似于指针类型的信息
(类模板) [编辑]