Re: [boost] warning C4275 with VC++ (non dll-interface class...) (again)

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-08-24 01:45:44

Luke Elliott wrote:

> 
> (BTW - I just used program_options as an example as that's what I was
> looking at at the time...)
> 
> I don't have access to VC++ right now so this is from memory, but there
> are (at least) 2 cases where it raises a warning:
> 
> class MY_LIB_DECL my_class : public some_base
> {
>      my_class();
> };
> 
> if some_base isn't a declspeced class then you get "warning non
> dll-interface class used as based for dll-interface class".

I believe this sometime happen when inheriting boost::noncopyable, that has
no method to begin with, right? Then it's indeed poor compiler diagnostic,
and we probably can add declspec, but I don't yet understand when it should
be dllexport and when dllimport :-/

> class MY_LIB_DECL my_class
> {
>      my_class();
> 
>      std::string  m_string;
> };

Does this happen with any boost library?

> However, the warnings can be removed by exporting only members which
> truly need to be exported - I was just curious as to why it isn't done
> in boost (possibly GCC issues?).

Truly, have no idea if GCC allows visibility attribute on methods.

- Volodya