Hi, Just wondering the difference between library builded with Jam and library builded with specifics target compiler's makefiles. For sample I think about the regex lib under VC6 which gives with nmake -f vc6.mak : boost_regex_vc6_mss.lib boost_regex_vc6_sssd.lib boost_regex_vc6_sssd.pdb boost_regex_vc6_mssd.lib boost_regex_vc6_mssd.pdb boost_regex_vc6_mdid.lib boost_regex_vc6_mdid.dll boost_regex_vc6_mdid.pdb boost_regex_vc6_mdi.lib boost_regex_vc6_mdi.dll boost_regex_vc6_mds.lib boost_regex_vc6_mdsd.lib boost_regex_vc6_mdsd.pdb and Jam that will give us : boost_regex.dll boost_regex.lib boost_regex_debug.dll boost_regex_debug.lib This is because the boost config/*.hpp file does not let me the choice. only the makefiles library seems to work. Thanks in advance. Alex