Subject: Re: [boost] [testing] Add a tester with hidden visibility
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2015-05-07 11:59:22
On Thursday 07 May 2015 16:45:22 Niall Douglas wrote:
> On 7 May 2015 at 7:54, Robert Ramey wrote:
> > So I had to update the source code to support the attributes for symbol
> > export on those functions which need to be exported. It sounds simple,
> > but getting this right in a way that supports both gcc and MSVC is tricky
> > and hard to get correct. I got the gcc to build and pass all test, but
> > now the MSVC is broken. Unfortunately, our testing system truncates the
> > error message so I can't see why the current branch in develop fails to
> > build. I'm still waiting from a response from the boost build team.
>
> I have no idea why you continue to insist on trying to second guess
> the very well established pattern here. The design of the GCC
> visibility support was chosen back in 2004 to correctly support all
> combinations of GCC, MSVC and Mingw without any special casing,
> trickery, or any macro work above the traditional preprocessor logic
> used for MSVC.
Well, it's not that simple. For example, if you dllexport a class template and
explicitly instantiate it in a dll with a non-exported type as a template
parameter, you will get what you want - an exported specialization. Hidden
visibility, OTOH, is viral, so the instantiated template will silently become
hidden in this case.
Other than that, yes, it's rather similar to MSVC.