I built Boost 1.38 (and earlier) with the following options --buildid=xxxx --layout=system This resulted in libs named libboost_regex-mt-xxxx.so With Boost 1.39 the libs (they *are* built with multi-threading support) are named 'only' libboost_regex-xxxx.so (note the missing "-mt") When linking against Boost libs I have written -lboost_regex-mt-xxxx in my code. Was that a bad idea (I mean the including -mt part)? I can fix this by passing --buildid=mt-xxxx to get the old names, but I am curious if that change was done on purpose. (I would like to avoid having to change Boost libs' names in my makefiles with every second Boost release or so ;-) So, to make the questions clear: 1) why was the change made? 2) is linking against sth like -lboost_regex-mt a bad idea? If so, why? 3) will the new naming remain? Best regards, and thanks a bunch for a bunch of helpful libs Christoph