Hi, Despite the fact that https://svn.boost.org/trac/boost/ticket/5292 has been sitting there for some time, the documentations still states that MPI_Allgatherv => most uses supported by all_gather (from 1.51.1). It seems the ticket wasn't commited nor refused. Is there a reason why a c++ MPI_gatherv equivalent is useless in Boost.MPI ? Overall, there seems to be a few other tickets in the same situation in the mpi lib. Which raises another question: what is the exact status of Boost.MPI ? is it still maintained ? is it worth submitting tickets or proposing patches to it or is it safer to move back to the C API ? Best regards Alain