Function mpi::ffi::PMPI_Neighbor_allgatherv

pub unsafe extern fn PMPI_Neighbor_allgatherv(sendbuf: *const c_void,
                                              sendcount: c_int,
                                              sendtype: MPI_Datatype,
                                              recvbuf: *mut c_void,
                                              recvcounts: *const c_int,
                                              displs: *const c_int,
                                              recvtype: MPI_Datatype,
                                              comm: MPI_Comm)
                                              -> c_int