Re: [boost] casting smart pointer

From: Jonathan Wakely (cow_at_[hidden])
Date: 2004-12-03 11:10:07

On Fri, Dec 03, 2004 at 04:59:10PM +0100, Dirk Gregorius wrote:

> Hi,
> 
> how can I upcast a shared_ptr?
> 
> class Base { /* ... */ }
> class Derived : public Base { /* ... */ }
> 
> shared_ptr<Base> Get( const char* pName );
> 
> shared_ptr<Derived> spDerived = *_cast<*>(  Get( "Derived" ) );  // What 
> do I need to write instead the * ?
> 

That's a downcast, isn't it?

You want static_pointer_cast<Derived>( Get("Derived") );

Defined in the same header as shared_ptr.

> Depending on the passed name I like to upcast the returned pointer to a 
> pointer to the derived class. I used a static_cast with raw pointers 
> before. What do I have to use with shared_ptr? Do I need to enable RTTI?

Only if you want to use dynamic_pointer_cast.

jon

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