Looking at the file boost/iostreams/chain.hpp I am pretty sure that at least this file has never been merged from RC_1_33_0 to HEAD. OTOH, the file char_traits.hpp seems to have been merged. So it looks like the library currently is in an inconsistent state or at least missing some fixes from the 1.33 release branch, could the author of the library please take a look at this? Markus