Any clues? I am trying to rebuild an app that worked with boost_1_31_0 and gcc3.3, now with gcc3.4. I completely rebuilt boost_1_31_0 libs using: PYTHON_ROOT=/usr PYTHON_VERSION=2.3 bjam -sTOOLS=gcc -sGXX=g++34 -sGCC=gcc34 PYTHON_ROOT=/usr PYTHON_VERSION=2.3 bjam -sTOOLS=gcc -sGXX=g++34 -sGCC=gcc34 stage Then I clean out all objects from my build, and rebuilt with g++34, but I got this error: g++34 -Wl,-rpath,/usr/local/src/boost_1_31_0.gcc34/stage/lib,-rpath,./ -o Test2 Test2.o -L/usr/local/src/boost_1_31_0.gcc34/stage/lib -L. -lshannon -lboost_program_options-gcc -lrfftw -lfftw Test2.o(.text+0x7d6e): In function `global constructors keyed to _Z21DesignImpulseResponseRKN10__gnu_norm6vectorISt7complexIdESaIS2_EEE_GCOV': /home/nbecker/shannon/TestAloha/Test2.cc:360: undefined reference to `__gcov_init'