Re: [cxx-conversion] Support garbage-collected C++ templates

[Diego Novillo <dnovillo at google dot com>]

On 12-08-08 16:12 , Gabriel Dos Reis wrote:
> hi Diego,
>
> just a word on style in the documentation:
>
> > +template<typename T>
> > +void gt_pch_nx (TP<T> *tp)
> > +@{
> > +  extern void gt_pch_nx (T&);
> > +
> > +  /* This marks field 'fld' of type 'T'.  */
> > +  gt_pch_nx (tp->fld);
> > +@}
>
> 'extern'  declaration at local scope if considered an extremely
> poor style in C++.  Furthermore, it does not interact
> well with template instantiations and scope rules; plus
> it does not work well when the function actually has an
> internal linkage.
>
> A proper way to bring a symbol into local scope is through
> a using-declaration:
>
>       using ::gt_pch_nx;

I struggled a bit with this. I need to tell the template function that 
there exists a free function gt_pch_nx that takes a T&. This is not 
something that any header file has at the point of this declaration.

The function gt_pch_nx(T&) is declared and defined later in one of the 
gt-*.h files.  This is another problem with the way that gengtype works 
today.

The using-declaration that you propose does not seem to give me what I 
want, though. How does it know that the function takes a T&?


Diego.