Re: [Boost-users] Problem with weak_ptr exception

Subject: Re: [Boost-users] Problem with weak_ptr exception
From: Nigel Rantor (wiggly_at_[hidden])
Date: 2009-10-28 10:39:33

Jacob Carlborg wrote:
> On 10/28/09 15:56, Stefan Strasser wrote:
>> I can't make sense of your code ("weakThis" in both A and B, even 
>> though B is
>> derived from A?), but have a look at boost::shared_from_this
> 
> If I don't have a weak_ptr in B I get this error when trying to create a 
> shared_ptr<B> from a weak_ptr<A>:
> /shared_ptr.hpp:207: error: invalid conversion from 'A* const' to 'B*'

The compiler is stopping you from doing something unsafe.

> I've already tried boost::shared_from_this and it gives me the same result.

I think it would be useful to show what you're actually trying to 
achieve becasue you can probably do it with shared_from_this(), and if 
you can't then it looks like it's because of casting issues rather than 
the shared_from_this code...

   n