the name mangled function that is exported is ?leaf@path@filesystem@boost@@QBE?AV?$basic_string@DU?$char_traits@D@std@@V?$ allocator@D@2@@std@@XZ but the function that msvc tries to link with is: ?leaf@path@filesystem@boost@@QBE?AV?$basic_string@DV?$char_traits@D@_STL@@V? $allocator@D@2@@_STL@@XZ Two things I've noticed that are a bit wierd are that the boost libs are put in stlport-4.5.3 directory even when built with the options directing it to 4.6. Also stlport has an option to put itself in the std namespace but merely #defines std as _STL so I would have expected the exported function from the boost library to be _STL not std. Any ideas, ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The msvc-stlport toolset doesn't currently work as advertised - I've posted a bug report on this but can't find a bjam expert to figure out what's wrong. Basically the STLPORT_VERSION macro gets ignored, it does work however if you put <stlport-version>4.6 in your BUILD variable. I'd advise running again with the -d2 option so you can check the command line options actually used. Failing that build it in your IDE - in fact that's probably the easiest option if you can't get bjam to work. John.