The mpich-3.2.1 built in the FreeBSD port has this problem of missing function when other project tries to link with it: /usr/bin/c++  -O2 -pipe -fno-omit-frame-pointer -fstack-protector -fno-strict-aliasing -fno-omit-frame-pointer -ffast-math -pthread -std=c++11 -O2 -pipe -fno-omit-frame-pointer -fstack-protector -fno-strict-aliasing -fno-omit-frame-pointer /usr/local/lib/libmpir.so -Wl,-rpath=/usr/local/lib/gcc7 -L/usr/local/lib/gcc7 -B/usr/local/bin -fstack-protector CMakeFiles/ssages.dir/src/main.cpp.o CMakeFiles/ssages.dir/hooks/lammps/Driver.cpp.o  -o ssages -L/usr/local/mpi/openmpi/lib/libmpi_cxx.so -L/usr/local/mpi/openmpi/lib/libmpi.so -L/usr/ports/science/ssages/work/SSAGES-public-0.8.3-alpha/_lammps_/src -Wl,-rpath,/usr/local/mpi/openmpi/lib/libmpi_cxx.so:/usr/local/mpi/openmpi/lib/libmpi.so:/usr/ports/science/ssages/work/SSAGES-public-0.8.3-alpha/_lammps_/src:/usr/local/mpi/openmpi/lib libssages.a -llammps_mpi /usr/local/mpi/openmpi/lib/libmpi_cxx.so /usr/local/mpi/openmpi/lib/libmpi.so CMakeFiles/ssages.dir/hooks/lammps/Driver.cpp.o: In function `SSAGES::Driver::Run()': Driver.cpp:(.text+0x3f): undefined reference to `LAMMPS_NS::LAMMPS::LAMMPS(int, char**, ompi_communicator_t*)' //usr/local/lib/libmpicxx.so.12: undefined reference to `MPIR_Keyval_set_proxy' //usr/local/lib/libmpicxx.so.12: undefined reference to `MPIR_Errhandler_set_cxx' //usr/local/lib/libmpicxx.so.12: undefined reference to `MPIR_Op_set_cxx' These functions are either missing from this library, or it isn't linked to some ther library. Yuri