RE: [boost] shared_ptr, interface and dlls

From: Stefan Seefeld (sseefeld_at_[hidden])
Date: 2004-12-08 11:29:24

> > extern "C" InterfacePtr DLLCreate( void )
> > {
> >    return InterfacePtr( new InterfaceImpl );
> > }
> >
> > At the moment this code doesn't compile because VS7.1 complains that
> > it a function with extern "C" linkage can't return a
> > shared_ptr<Interface> instance. How could I implement the desired
> > behavior?
> 
> Either omit the extern "C" or, if you must use a C-style 
> interface, do this:
> 
> extern "C" Interface* DLLCreate()
> {
>     return new InterfaceImpl;
> }
> 
> extern "C" void DLLDestroy( Interface* p )
> {
>     delete p;
> }
> 
> and then construct an InterfacePtr( DLLCreate(), DLLDestroy 
> ). You'll need a 
> public virtual destructor in this case, though.

When writing plugins under linux (i.e. with 'dlopen' etc.),
I believe I have already used a function returning a std::auto_ptr as
entry point for the loader. What is wrong with that ? Is your advice
above simply due to a limitation with MSVC ?

Regards,
                Stefan