Hi, I've run into a problem since adding a dependency on boost_thread. My shared library no longer loads (via dlopen("libmy.so",RTLD_NOW), I get error: undefined symbol: _ZTIN5boost6detail16thread_data_baseE Any ideas on how to resolve this? Details: OS - CentOS 5.4, x86_64 Boost version - 1.47.0 built from source ./bootstrap.sh --with-libraries=exception,filesystem,math,thread --prefix=/usr/local/boost_1_47_0 ./b2 install This worked fine. Although I built the other boost libraries, I'm only using thread at this time. Link line for my shared library which uses boost thread: Building target: libtslib.so Invoking: GCC C++ Linker g++ -L"/usr/local/boost_1_47_0/lib" -L"/opt/xerces-c-3.1.0-x86_64-linux-gcc-3.4/lib" -L"/home/Greg/workspace/geothreadcpp/Release" -L"/home/Greg/workspace/geothreadcpp/Debug" -L"/home/Greg/workspace/geocosmexception/Release" -L"/home/Greg/workspace/geocosmxmllibbasecpp/Release" -L"/home/Greg/workspace/xmllib/Release" -L"/mnt/src/geocosm/matlab/geneticalglib/galibcmplinux_x86_64/distrib" -shared -o"libtslib.so" ./tslibcpp/src/TsLibCpp.o ./tslib/src/tslibresults.o ./tslib/src/tslibsamplematch.o -lmlgalib -lpthread -lgeothreadcpp -lgeocosmexception -lxerces-c-3.1 -lgeocosmxmllibbasecpp -lxmllib Finished building target: libtslib.so note it is relying on the auto link boost feature which seems to correctly use the static lib version of boost_thread as "ldd" does not report a dependency on boost_thread: ldd libtslib.so libmlgalib.so => not found libpthread.so.0 => /lib64/libpthread.so.0 (0x00002aae15ec3000) libgeothreadcpp.so => not found libgeocosmexception.so => not found libxerces-c-3.1.so => not found libgeocosmxmllibbasecpp.so => not found libxmllib.so => not found libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00002aae160e0000) libm.so.6 => /lib64/libm.so.6 (0x00002aae163e0000) libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00002aae16664000) libc.so.6 => /lib64/libc.so.6 (0x00002aae16872000) /lib64/ld-linux-x86-64.so.2 (0x00000036c7a00000) When my application attempts to load my shared library via dlopen I get the undefined symbol error. If I explicitly link to the shared lib version of boost_thread, ldd shows a dependency (which it should). If I then include a copy of boost_thread .so on the ld path my shared library loads without problems. However this is what I wanted to avoid and instead embed lib boost_thread directly into my .so. Thanks for any insight. Greg.