Hello all, I noticed that MPICH 3.1.1 changed which libraries symbols go in. The MPI_*_c2f functions are no longer available to source files compiled with mpicc and mpicxx (unless you explicitly add -lmpifort). In our opinion the MPI_*_c2f and MPI_* symbols should be available from all compiler drivers (mpicc, mpicxx, mpif77, mpif90, etc.) without the need to explicitly add -lmpifort. Since they are used to convert values between C and Fortran and vice versa it is natural that one would want to use them from both languages. Existing code which assumes, I believe quite reasonably, that MPI_*_c2f, etc. can be used from mpicc with no extra effort fails to compile with MPICH 3.1.1. I think this is a regression which should be fixed. Yours, Chris January - VP Engineering - Allinea Software Ltd.