Separate messages from stdout and stderr of a port

[Alexey Romanov]

I can get the output of a spawned port on its stderr stream by using
stderr_to_stdout. However,
is there a way to get messages from the port's stdout and stderr
separately? I don't see one in
http://www.erlang.org/doc/man/erlang.html
In fact, it would be enough for my purposes to only get stderr and
ignore stdout.

Yours, Alexey Romanov