On Monday 08 June 2009 01:16:13 Vladimir Prus wrote:
Andrey Semashev wrote:
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.
I guess, someone has already fixed it then. Splendid.
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?
No, if it's header-only. That's one of the problems with the patch: such exceptions should not be marked in any way for MSVC (and other compilers with the similar type_info support), but should always have default visibility for GCC on Linux.
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?
Unless we're banning visibility=hidden, it may matter. IIRC, Boost.Exception uses type_info to acquire error_info at the catch site. If it isn't exported, the acquisition will fail, because type_infos will not match. Oh, and for the same reason boost::exception should be exported, too, as it can be used to catch exceptions or as a target type for dynamic_casts. However, I'm not that familiar with the library implementation to be absolutely sure. I hope that the library maintainer is reading this.