Function mpi::ffi::MPI_Dist_graph_neighbors

pub unsafe extern fn MPI_Dist_graph_neighbors(comm: MPI_Comm,
                                              maxindegree: c_int,
                                              sources: *mut c_int,
                                              sourceweights: *mut c_int,
                                              maxoutdegree: c_int,
                                              destinations: *mut c_int,
                                              destweights: *mut c_int)
                                              -> c_int