Function q_decode_cols 

pub unsafe extern "C" fn q_decode_cols(
    resp: *mut u8,
    resp_len: i64,
    compressed: c_int,
    cols: *const *const c_char,
    ncols: c_int,
    err: *mut c_char,
    errlen: usize,
) -> *mut ray_t

As q_decode, but a table comes back with only the ncols columns named in cols, in the order named (q’s cols#t). The other columns are skipped by their serialized length: nothing is allocated or interned for them, and a column q_decode rejects (a timespan) can be skipped. For a keyed table the key comes back whole and the names pick among the value columns. A name the table lacks is a RAY_ERROR naming it; a null or repeated name returns null with err set. With ncols == 0, or a message that is not a table, this is q_decode. Since rayforce-q 2.5.0. Engine thread only.