let to_string ?r =
function
| None -> "infinity"
| Some l ->
(match r with
| None -> Int64.to_string l
| Some RLIMIT_CORE | Some RLIMIT_DATA | Some RLIMIT_FSIZE |
Some RLIMIT_STACK | Some RLIMIT_AS -> string_of_bytes l
| Some RLIMIT_NOFILE -> Int64.to_string l
| Some RLIMIT_CPU -> Printf.sprintf "%Ld s" l)