From: Philippe A. Bouchard (philippeb_at_[hidden])
Date: 2003-02-27 09:28:14
"Philippe A. Bouchard" <philippeb_at_[hidden]> wrote in message
news:b3hcea$gri$1_at_main.gmane.org...
[...]
> int main()
> {
> optional<B> b;
> optional<C> c;
>
> foo(b);
> //foo(c);
> }
BTW implicit cast to reference types are not implicit under GCC, they have
to be called explicitly. Template casts do not seem to be defined in the
standard...:
template <typename T>
struct optional
{
template <typename U>
operator optional<U> const & () const
{
return * reinterpret_cast<optional<U> const *>(static_cast<U
const *>(reinterpret_cast<T const *>(storage_)));
}
...
};
inline void foo(optional<A> const &)
{
}
int main()
{
optional<B> b;
//foo(b);
foo(b.template operator optional<A> const & <A> ());
}
Also, the advantage of casts to reference types is that they do not create
any temporary objects implicitly. I do not see in what it can be dangerous.
What do you think?
Philippe A. Bouchard