This is in cygwin, using gcc. initially I used the following (I don't use python and don't have MPI, but wanted everything else): $ ./bootstrap.sh --with-libraries=chrono,date_time,exception,filesystem,graph,graph_parallel, iostreams,math,program_options,random,regex,serialization,signals,system,tes t,thread,wave ./b2 install I then tried building QuantLib, which makes extensive use of boost, including the test framework. But it failed because it tried linking to a multihtreaded build of the test frameqwork. I therefore tried the following, assuming that like make, it would just build and install those targets that had not been built the first time. $ ./bootstrap.sh --with-libraries=chrono,date_time,exception,filesystem,graph,graph_parallel, iostreams,math,program_options,random,regex,serialization,signals,system,tes t,thread,wave link=static link=shared threading=single threading=multi ./b2 install Unfortunately, it did not create the multithreaded build of the testframework that QuantLib requires. What did I miss that is preventing me from getting the multihtreaded builds of the required libraries? Thanks Ted