Re: Rewriting clone() to return a boost::shared_ptr ?

helix wrote:


Yes, that will work fine. There is, however, one drawback, in that you
cannot use covariant return types. Consider the following:

class A
{
public:
    virtual A* clone() = 0;
};

class B
{
public:
    virtual B* clone(); // Covariant return type.
};

There may be cases where you have a pointer to B, and you want to clone
the object to get another pointer to B, perhaps to do something through
some B specific member functions. Only pointers and references can be
covariant, however. Consider the following:

class A
{
public:
    virtual boost::shared_ptr<A> clone() = 0;
};

class B
{
public:
    virtual boost::shared_ptr<B> clone(); // Can't do this! Not a pointer.
};

--
Alan Johnson

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