on Thu Jul 10 2008, Steven Watanabe <watanabesj-AT-gmail.com> wrote:
AMDG
I'm looking at two recent posts: http://comments.gmane.org/gmane.comp.lib.boost.devel/177370 http://comments.gmane.org/gmane.comp.lib.boost.user/37476
Either of these is fine by itself, but putting them both together makes it very easy to cause silent ODR problems.
Heh, I just noticed the same issue.
For example in translation unit a.cpp we #include "boost/tuple/tuple_io.hpp" and translation unit b.cpp we forget. Then, along comes boost::any which detects operator<< in translation unit a.cpp, but uses its default in translation unit b.cpp. Ka-Boom.
This is not a huge problem at the moment, because it's quite difficult to make the detection bullet-proof,
I don't think that accurately characterizes the issue. I think few compilers do anything to detect ODR violations. However, link-time stripping of common template instantiations (or link-time instantiation) seems likely to cause only a single behavior in both TUs where two behaviors may have been intended.
but I'm very concerned because C++0x concepts are supposed to make such overloading easy.
I'm not sure I see the relationship to C++0x concepts. Care to say more? -- Dave Abrahams BoostPro Computing http://www.boostpro.com