The error (undefined reference) clearly is in the linking step. For example, I get export BINDIR=/home/mahmood/gpgpu-sim_distribution/ispass2009-benchmarks/bin/; export ROOTDIR=/home/mahmood/NVIDIA_GPU_Computing_SDK/C/src/; export BINSUBDIR=release; export BOOST_LIB=/home/mahmood/boost_1_40_0/lib; export BOOST_ROOT=/home/mahmood/boost_1_40_0; export BOOST_VER=""; export OPENMPI_BINDIR=/usr/bin/; make noinline=0 -C AES make[1]: Entering directory `/home/mahmood/gpgpu-sim_distribution/ispass2009-benchmarks/AES' obj/x86_64/release/aescuda.cpp.o: In function `_GLOBAL__sub_I_aescuda.cpp': aescuda.cpp:(.text.startup+0x68b): undefined reference to `boost::system::get_system_category()' aescuda.cpp:(.text.startup+0x697): undefined reference to `boost::system::get_generic_category()' aescuda.cpp:(.text.startup+0x6a3): undefined reference to `boost::system::get_generic_category()' aescuda.cpp:(.text.startup+0x6af): undefined reference to `boost::system::get_generic_category()' aescuda.cpp:(.text.startup+0x6bb): undefined reference to `boost::system::get_system_category()' And AES/Makefile contains LINKFLAGS := -L$(BOOST_LIB) As you can see the BOOST_LIB variable points to /home/mahmood/boost_1_40_0/lib and such functions are in the library files mahmood@vb:boost_1_40_0$ grep -r get_system_category lib Binary file lib/libboost_system.so.1.40.0 matches Binary file lib/libboost_system.so matches Binary file lib/libboost_system.a matches Binary file lib/libboost_filesystem.a matches Binary file lib/libboost_filesystem.so matches Binary file lib/libboost_filesystem.so.1.40.0 matches So, all things look normal. Isn’t that? Why I got that error? Regards, Mahmood Sent from Mail for Windows 10