On Mon, Nov 14, 2016 at 8:47 PM, Sean McBride <s...@rogue-research.com> wrote:
> On Thu, 10 Nov 2016 14:11:59 -0500, Marcus D. Hanwell said: > > >I would be interested in further details on which case or cases are > >causing dynamic_cast to fail, and why using consistent symbol > >visibility in the interfaces is not feasible/possible. > > I'm not really following this issue, but... > > Is this really a Mac OS X issue, or is it being conflated with clang? > That is, does the issue happen with clang on linux for example? Is it only > Apple's fork or clang, or the open source one too? Does it happen with gcc > on Mac OS X? etc. > The compiler ABI rules and behavior have not changed. What has changed is that OS X linker fallbacks have been removed [1], and Slicer (and perhaps ITK itself by default, I haven't spelunked the log) have set the default symbol visibility to hidden, which means that (now-hidden) type_info symbols are not coalesced across compilation unit boundaries. I would recommend this summary of the issue from a libreoffice commit message [2], as well as the summary linked in a previous message [3]. Recent libstdc++ have reinstated a strcmp fallback [4], so the issue is unlikely to be encountered on most Linux distributions. [1] On OS X, my understanding is that libc++ (cxxabi) was compiled with "_LIBCXX_DYNAMIC_FALLBACK" until OS X 10.11, which causes a fallback to strcmp comparison of the type_info name (10.11 still contains a program name-based fallback for two Adobe products that Apple could not reasonably break). [2] https://lists.freedesktop.org/archives/libreoffice-commits/2015-January/091572.html [3] http://www.russellmcc.com/posts/2013-08-03-rtti.html [4] https://gcc.gnu.org/ml/gcc-patches/2009-07/msg01239.html > > Cheers, > > -- > ____________________________________________________________ > Sean McBride, B. Eng s...@rogue-research.com > Rogue Research www.rogue-research.com > Mac Software Developer Montréal, Québec, Canada > > > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Kitware offers ITK Training Courses, for more information visit: > http://kitware.com/products/protraining.php > > Please keep messages on-topic and check the ITK FAQ at: > http://www.itk.org/Wiki/ITK_FAQ > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/insight-developers >
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