Re: [boost] support for gcc hidden visibility in shared libraries

Subject: Re: [boost] support for gcc hidden visibility in shared libraries
From: Stjepan Rajko (stjepan.rajko_at_[hidden])
Date: 2008-12-05 15:47:32

On Fri, Dec 5, 2008 at 12:12 PM, Andrey Semashev
<andrey.semashev_at_[hidden]> wrote:
>
> [snip problems with -fvisibility=hidden]
>

Thanks for the clarifications. (perhaps this is related to what Mat
Marcus was hinting about?)

>
> So it doesn't look like a trivial change in settings and macros to me.
> What's worst, making such a change can trigger problems that are hardly
> detected by unit tests. Perhaps, we should just mandate the
> visibility=hidden mode not supported for now. Maybe
> --fvisibility-ms-compat or --fvisibility-inlines-hidden would be a
> better choice to support?

Sounds good to me, like I said my understanding of this is limited.
It looks like the list of possible changes, in the order of potential
breakage danger are:

1. add BOOST_SYMBOL_EXPORT / IMPORT config macros [this breaks nothing]
2. modify existing boost libraries that use similar macros of their
own to use the boost.config macros [if the functionality of the new
macros is a superset of the old macros, shouldn't break anything]
3. modify the default boost build to use -fvisibility-ms-compat or
--fvisibility-inlines-hidden [low risk?]
4. modify the default boost build to use -fvisibility-hidden [high risk?]

The patch by Alexander Arhipenko does 1,2, and 4.  Perhaps we can at
least start with 1, or 1 and 2?

Stjepan