Ruby 4.1 リファレンスマニュアル

module function Kernel?.select

select(reads, writes = [], excepts = [], timeout = nil) -> [[IO]] | nil[permalink][rdoc][edit]
(::Array[IO] read, ?::Array[IO] write, ?::Array[IO] error, ?Time::_Timeout timeout) → ::Array[String]

IO.select と同じです。

[PARAM] reads:
IO.select 参照
[PARAM] writes:
IO.select 参照
[PARAM] excepts:
IO.select 参照
[PARAM] timeout:
IO.select 参照

[SEE_ALSO] IO.select