From: Eric Hodel <drbrain@...7.net>
Date: 2009-05-20T13:38:53+09:00
Subject: Re: I want to redirect stderr to StringIO.

On May 19, 2009, at 21:30, ErMaker wrote:

>>> IO.new(2).reopen(StringIO.new)
> TypeError: can't convert StringIO into String
>        from (irb):1:in `reopen'
>        from (irb):1
>>> IO.new(2).reopen(IO.new(1))
> => #<IO:0x2a81630>
>
> StringIO also do as IO, but IO#reopen fails.
>
> I want to redirect stderr to StringIO, but it doesn't work.

Always use reopen as a last resort.

http://blog.segment7.net/articles/2006/08/17/stdout-vs-stdout