Hello, I don't know if this mailing list is the best place to file a bug report (maybe better on the boost-developers mailing list, or on bugzilla if there is one) to get something fixed, but I have a problem with type_traits. I am not using type_traits directly, only through use of the BGL. I got the following error (which was posted in a previous message related to the BGL, before I discovered that the error was in type_traits - sorry!): In file included from /Users/elvanor/Development/boost/boost/type_traits/extent.hpp:14, from /Users/elvanor/Development/boost/boost/type_traits.hpp:61, from /Users/elvanor/Development/boost/boost/detail/numeric_traits.hpp:64, from /Users/elvanor/Development/boost/boost/iterator/counting_iterator.hpp: 9, from /Users/elvanor/Development/boost/boost/pending/integer_range.hpp:14, from /Users/elvanor/Development/boost/boost/graph/detail/adjacency_list.hpp: 18, from /Users/elvanor/Development/boost/boost/graph/adjacency_list.hpp:281, from /Users/elvanor/Development/probabilisticgraphicalmodels/src/ GraphAlgorithms.h:4, from /Users/elvanor/Development/probabilisticgraphicalmodels/src/ GraphAlgorithms.cc:7: /Users/elvanor/Development/boost/boost/type_traits/detail/ size_t_trait_def.hpp:33:1: "BOOST_TT_AUX_SIZE_T_TRAIT_DEF1" redefined In file included from /Users/elvanor/Development/boost/boost/type_traits/rank.hpp:14, from /Users/elvanor/Development/boost/boost/type_traits.hpp:60, from /Users/elvanor/Development/boost/boost/detail/numeric_traits.hpp:64, from /Users/elvanor/Development/boost/boost/iterator/counting_iterator.hpp: 9, from /Users/elvanor/Development/boost/boost/pending/integer_range.hpp:14, from /Users/elvanor/Development/boost/boost/graph/detail/adjacency_list.hpp: 18, from /Users/elvanor/Development/boost/boost/graph/adjacency_list.hpp:281, from /Users/elvanor/Development/probabilisticgraphicalmodels/src/ GraphAlgorithms.h:4, from /Users/elvanor/Development/probabilisticgraphicalmodels/src/ GraphAlgorithms.cc:7: /Users/elvanor/Development/boost/boost/type_traits/detail/ size_t_trait_def.hpp:33:1: this is the location of the previous definition I have looked in the file producing the error (multiple defines). It doesn't include a header guard, but the file specifically says that this is intentional. Thus, I am not qualified enough to get a quick fix for my situation, and this is a problem since I really need the CVS version of Boost for my project... I tried replacing the whole type_traits directory from CVS with the one from Boost 1.32 (because i hadn't any problems with typetraits and Boost Graph Library until today, when I replaced 1.32 with CVS) , but I then get tons of compiler errors when compiling my project so obviously it isn't a good idea. Jean-Noël Rivasseau