Re: [boost] weak_ptr, maybe empty

From: Michael B. Edwin Rickert (panda_at_[hidden])
Date: 2005-08-03 15:13:54

Andy Thomas-Cramer wrote:
> I have a weak_ptr that might be empty. If not empty, I'd like to make a
> smart pointer from it. 
>  
> But the code below throws in the shared_ptr constructor, and I don't see
> how to test whether a weak_ptr is empty.
> 
>     boost::weak_ptr<int> wp;
>     boost::shared_ptr<int> sp(wp);
>     if ( sp.get() ) {
>         ...
>     }

The documentation (http://boost.org/libs/smart_ptr/weak_ptr.htm) seems 
to show a few options. The most similar to your situation would be:

boost::weak_ptr< int > wp;
boost::shared_ptr< int > sp = wp.lock();
if ( sp.get() ) {
     ...
}