function template
<memory>

std::addressof

template <class T> T* addressof (T& ref) noexcept;
Address of object or function
Returns the address of the object or function referenced by ref.

This function returns the address of ref even in the presence of an overloaded reference operator (operator&).

Parameters

ref
An object or function.

Return value

A pointer to the object or function.

Example

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// addressof example
#include <iostream>
#include <memory>

struct unreferenceable {
  int x;
  unreferenceable* operator&() { return nullptr; }
};

void print (unreferenceable* m) {
  if (m) std::cout << m->x << '\n';
  else std::cout << "[null pointer]\n";
}

int main () {
  void(*pfn)(unreferenceable*) = std::addressof(print);

  unreferenceable val {10};
  unreferenceable* foo = &val;
  unreferenceable* bar = std::addressof(val);

  (*pfn)(foo);   // prints [null pointer]
  (*pfn)(bar);   // prints 10

  return 0;
}


Output:
[null pointer]
10

C++