Should boost force symbol visibility if built as a static lib?

[epvbergen]

I'm consuming boost::asio as a static library in a project that is delivered as a shared library. To avoid conflicts in clients, I try to hide all symbols originating from my dependencies by linking with -Wl,--exclude-libs,ALL.

To my surprise, this does not work for boost::asio. A little research showed that at some point it was deemed a good idea to force default visibility on exception typeinfo and support classes for printing the exceptions from boost, see eg. https://svn.boost.org/trac10/ticket/4594 which proposed a #pragma visibility push default, only conditional on the compiler. So regardless of whether boost is built as a static or a dynamic library, the symbols get marked with default visibility on GCC.

And now I wonder if this is really the correct policy, or if boost (and any library) should rather refrain from explicitly setting visibility attributes when building a static library. Doesn't that make more sense?

Right now I have a nasty symbol leak that causes conflicts in my clients using a different version of asio. Updated: the problem has been reported before, along with a possible solution, see https://svn.boost.org/trac10/ticket/12722.

[apolukhin]

Good point. Could you please move that issue to the https://github.com/boostorg/config repo. Fixing it there will fix all the boost libraries in one go.

[epvbergen]

Thanks, it's now at boostorg/config#243

[mzeren-vmw]

I'm a bit confused. How does moving this bug to config fix:
https://github.com/boostorg/asio/blob/develop/include/boost/asio/detail/push_options.hpp#L26
See also: https://svn.boost.org/trac10/ticket/12722
Which we workaround by patching our Asio build to remove the visibility pragmas.