Re: Visibility and C++ Classes/Templates

[Jason Merrill <jason at redhat dot com>]

Gabriel Dos Reis wrote:
> Mark Mitchell <mark@codesourcery.com> writes:
> | I'm just not comfortable with the idea of #pragmas affecting
> | instantiations.  (I'm OK with them affecting specializations, though; in
> | that case, the original template has basically no impact, so I think
> | it's fine to treat the specialization case as if it were any other
> | function.)
>
> I'm undecided whether #pragmas should not affect explicit
> instantiations.  They really are not like implicit instantiations
> (which, I agree with you, should not be affected).  Explicit 
> instantiations behave more like real declarations than implicit
> instantiations. 

Yep.  I'm sympathetic to Mark's position, but still tend to believe that 
the #pragma should affect explicit instantiations.  Explicit 
instantiations are a way to make template instantiations conform more to 
the traditional declaration/definition model.  We ignore the #pragmas 
for implicit instantiations because the user doesn't control the point 
of instantiation; with explicit instantiations, they do.

Explicit instantiations don't behave just like implicit instantiations; 
there are other differences.

Jason