Just found a compilation problem in include/boost-1_35/boost/pool/detail/mutex.hpp line 67. While compiling with VS2005 under WinXp, got compilation error "C2872: 'CRITICAL_SECTION' : ambiguous symbol". ( project is quite complicated, with many includes and soon) Fix is trivial: ::CRITICAL_SECTION mtx; // note "::" to resolve symbol mix-up.