Re: [Boost-users] A question about shared_ptr

From: Tommy Hinks (tommy.hinks_at_[hidden])
Date: 2006-07-14 12:21:33

You can't pass 0 because the Type passed must be an Investment*, not
just a type that could be cast to one. This is why you have to
explicitly cast it yourself.

Tommy

On 14/07/06, Zhuo Hao <hzhuo1_at_[hidden]> wrote:
> In file <boost/shared_ptr.hpp>, I find the following function:
> /begin quote
> template<class Y, class D> shared_ptr(Y * p, D d): px(p), pn(p, d)
>     {
>         detail::sp_enable_shared_from_this( pn, p, p );
>     }
> /end quote
> If I use it as follows:"boost::shared_ptr<Investment>
> pInv(0,getRidOfInvestment)",it will not compile.But when I
> use:"boost::shared_ptr<Investment>
> pInv(static_cast<Investment*>(0),getRidOfInvestment)",it
> can be compiled.
> The constructor's first parameter is Y*,i.e.,a pointer to Y.And 0 can be
> interpreted as a pointer to Y,too.  Why  can't zero be treated as a pointer
> to Y here?
>
> I will be appreciative if anyone can give me some suggestions.Thank you!
>
> hzhuo
> July,14th
>
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