std::addressof
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| 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&
Inhaltsverzeichnis |
[Bearbeiten] Parameter
| arg | - | lvalue object or function |
[Bearbeiten] Rückgabewert
Pointer to arg.
[Bearbeiten] Ausnahmen
[Bearbeiten] Mögliche Implementierung
template< class T > T* addressof(T& arg) { return (T*)&(char&)arg; } |
[Bearbeiten] 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
[Bearbeiten] Siehe auch
| der Standardallokator (Klassen-Template) | |
| (C++11) |
liefert Informationen über zeigerähnliche Typen (Klassen-Template) |
