Function mpi::ffi::PMPI_Allgatherv

pub unsafe extern fn PMPI_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