module In_channel : sig ... endIn_channel collects all of the pervasive functions that work on in_channels.
module Out_channel : sig ... endval printf : ('a, Out_channel.t, Stdio__.Import.unit) Stdio__.Import.format ‑> 'aSame as Out_channel.printf
val eprintf : ('a, Out_channel.t, Stdio__.Import.unit) Stdio__.Import.format ‑> 'aSame as Out_channel.eprintf