Thanks for the reply but these three FAQs do not have the answer, I am afraid. The fist question is about an installed version of Boost. This one is always found and always used, but I want to use a staged version.The second question is about the number of tests used by ax_boost.m4. I don't care for that problem. The third question is about finding someone else's Boost and NOT having a staged version, but I *have* a staged version and I cannot convince "configure" to use it. I have tried: ../configure --with-boost=/home/jkr/src/boost_1_51_0 --with-boost-libdir=/home/jkr/src/boost_1_51_0/stage/lib It seems to find something, i.e. I see the following in my config.log and similar things if I run make: BOOST_CPPFLAGS='-I/home/jkr/src/boost_1_51_0/include' BOOST_LDFLAGS='-L/home/jkr/src/boost_1_51_0/stage/lib' BOOST_LIBS='-lboost_system-mt -lboost_serialization-mt -lboost_thread-mt -lboost_date_time-mt -lboost_filesystem-mt -lboost_regex-mt' Note that I had to symlink the "--with-boost"-directory to an "include"-directory in the same "--with-boost"-directory because "configure" appends "include" to the path. But if I do ldd on the executable I get: jkr@panoramix:~/sda/workspace/TestApp/linux$ ldd src/testapp | grep boost libboost_system.so.1.49.0 => /usr/lib/libboost_system.so.1.49.0 (0x00007f5145047000) libboost_serialization.so.1.49.0 => /usr/lib/libboost_serialization.so.1.49.0 (0x00007f5144dcc000) libboost_thread.so.1.49.0 => /usr/lib/libboost_thread.so.1.49.0 (0x00007f5144baf000) libboost_date_time.so.1.49.0 => /usr/lib/libboost_date_time.so.1.49.0 (0x00007f514499f000) libboost_filesystem.so.1.49.0 => /usr/lib/libboost_filesystem.so.1.49.0 (0x00007f514477f000) libboost_regex.so.1.49.0 => /usr/lib/libboost_regex.so.1.49.0 (0x00007f514445f000) So somehow the wrong boost version is used. An I cannot figure out why. -- Groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 web: www.askesis.nl