Re: Deprecated shared_polymorphic_cast
eca ha scritto:
I have learned that shared_*_pointer functions are deprecated
and *_pointer_cast equivalents should be used instead.
Is the following a good replacement for shared_polymorphic_cast?
// File: polymorphic_cast.h
#ifndef _EXTPOLYMORPHICCAST_H
#define _EXTPOLYMORPHICCAST_H
#include <boost/shared_ptr.hpp>
namespace ext {
template<class T, class U>
boost::shared_ptr<T> polymorphic_pointer_cast(boost::shared_ptr<U>
const & r)
{ return boost::shared_ptr<T>(r,
boost::detail::polymorphic_cast_tag()); }
}
#endif
Given that the shared_ptr<> constructor with the "tag" as second
parameter is undocumented, I'd steer away from that approach, especially
since there is a valid documented alternative using the aliasing
constructor:
template<class T, class U>
boost::shared_ptr<T>
polymorphic_pointer_cast(boost::shared_ptr<U> const & r)
{
return boost::shared_ptr<T>(r, boost::polymorphic_cast<T>(r.get());
}
(notice that the constructor is used with two parameters, not one.)
HTH,
Ganesh
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