std::addressof
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<metanoindex/>
<tbody> </tbody>| definiert in Header <memory>
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template< class T > T* addressof(T& arg); |
(seit C++11) | |
Obtains the actual address of the object or function arg, even in presence of overloaded operator&
Parameter
| arg | - | lvalue object or function |
Rückgabewert
Pointer to arg.
Ausnahmen
Mögliche Implementierung
template< class T >
T* addressof(T& arg) {
return (T*)&(char&)arg;
}
|
Beispiel
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
}
Output:
int** overload called with p = 0012FF64
Ptr overload called with p = 0012FF64