Andrey Semashev wrote:
Vladimir Prus wrote:
Over in issue 2114 (https://svn.boost.org/trac/boost/ticket/2114), Jürgen has provided a patch to add gcc visiblity support to all separately compiled libraries. gcc visibility is a mechanism similar to dllexport on Windows, with the same benefits.
I have tried to apply it, and rebuild program_options. The the size of release shared library went from 272K down to 224K. The number of relocations went from 972 to 872. Both changes seem to be good.
For the record, there was a discussion about visibility support and the patch:
http://lists.boost.org/Archives/boost/2008/12/146068.php
Last time I heard the patch broke program_options.
It appears to work now, though. I suspect this is because every exception in boost/program_options/errors.hpp is already marked with BOOST_PROGRAM_OPTIONS_DECL.
It seems to be unlikely to get the authors of every compiled library to look at the patch, so it looks like an alternative approach is necessary. Does anybody have any objections to this approach? If not, I'll check this in somewhere before Jule 15 deadline, and will take care of checking regression results afterwards.
Perhaps we could search for exception classes and mark them as exported right away? We could do this, e.g., by looking for throw_exception or throw expressions. A lot of work, I know, but it has to be done anyway.
Hmm, isn't every exception class supposed to be marked with BOOST_XXX_DECL anyway?
Maybe there are other procedures necessary to make sure it works. Boost.Exception comes to mind as a possible source of issues. It is related to both exceptions and dynamic_cast. I'm guessing, at least error_info should be exported, too.
I am unsure why -- it is ever used where typeid matters? - Volodya