Building Boost 1.41 against OpenSuSE 11.2 works fine... until you try to link a lib against a program: You get the following linker error: <path to boost_1_41_0>/lib/libboost_program_options-mt-Melos.so: undefined reference to `__sync_fetch_and_add_4' Googling around indicated that libc or something no longer supports i386 which is Boost's default -march setting for gcc. (see tools/build/v2/tools/gcc.jam) When I changed the default to i686 and rebuilt Boost, the program linked ok. [See: http://sourceware.org/ml/libc-alpha/2007-02/msg00009.html] I am not sure if this is not rather a bug in OpenSuSE 11.2, but it is annoying nevertheless. * Is there an easy way (I modified gcc.jam for my test) to configure -march? (Pleae see my post (yesterday) "Build boost for i686 (instead of i386)" in boost.user.) * Or maybe i386 is no longer a safe default to assume? Best regards, and thank you Christoph