CODEWITHSUNDEEP
c++std
GeneralFailure
GeneralFailure

Reputation: 1105

std::addressof - strange implementation

So a few days ago i learned about std::addressof. At http://en.cppreference.com/w/cpp/memory/addressof a possible implementation is given:

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

As far i see this can simply be implemented like:

template<typename T>
T* addressof( T& var )
{
    return &var;
}

Why the guys at cppreference chose to implement it with 3 casts? Is there any detail I am missing that is making their implementation better. What is the point in using volatile when all you do is cast?

Upvotes: 10

Views: 497

Answers (1)

juanchopanza
juanchopanza

Reputation: 227518

If it could be implemented like in your example, there would be no need for it. The point is that it gives you the address of an object, even if the address-of operator& for that type has been overloaded.

Upvotes: 9

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