Input, Output, PIDs, and Nodes
Input and output in the Erlang VM are performed using I/O servers. These are simply Erlang processes that implement a low-level message interface. You never have to deal with this interface directly (which is a good thing, as it is complex). Instead, you use the various Elixir and Erlang I/O libraries and let them do the heavy lifting.
In Elixir you identify an open file or device by the PID of its I/O server. And these PIDs behave like all other PIDs—you can, for example, send them between nodes. If you look at the implementation of Elixir’s IO.puts function, you’ll see
| def puts(device \\ group_leader(), item) do |
| erl_dev = map_dev(device) |
| :io.put_chars erl_dev, [to_iodata(item), ?\n] |
| end |
(To ...
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