Function PMPI_Unpack

pub unsafe extern "C" fn PMPI_Unpack(
    inbuf: *const c_void,
    insize: c_int,
    position: *mut c_int,
    outbuf: *mut c_void,
    outcount: c_int,
    datatype: MPI_Datatype,
    comm: MPI_Comm,
) -> c_int