Hello David, VP> So, the assertion only appears when using release version built using VP> \libs\python\build\VisualStudio\boost_python.dsw Correction: probably just release version built by anything, 'cause I didn't try bjammed release version. VP> I don't claim that it is Boost code that has an error---but surely VP> there _is_ a bug somewhere in there? Maybe MSVC projects, maybe MSVC VP> itself :) . After I built release Boost.Python version with "Multi-threaded Debug DLL" runtime, the assertion disappeared again. Hmm... I rather expected independency of app and Boost.Python in that matter. Should we call it "feature" then, instead of "bug" :) ? Pity that dox don't mention it. -- Best regards, Vladimir mailto:pvv@ugnn.ru