From: Robert Klemme <shortcutter@...>
Date: 2009-05-22T13:27:19+09:00
Subject: Re: I want to redirect stderr to StringIO.

On 20.05.2009 21:01, Eric Hodel wrote:
> On May 19, 2009, at 23:14, Robert Klemme wrote:
>> 2009/5/20 Eric Hodel <drbrain@segment7.net>:

>>> http://blog.segment7.net/articles/2006/08/17/stdout-vs-stdout
>> I am not sure I agree.  Actually, if you want the redirection to be
>> permanent for sub processes you have to use $stdout.reopen.  And this
>> is not a "last resort" but the proper solution.
> 
> Most of the time people capture IO from sub processes via Kernel#` or  
> IO::popen instead of handling the sub process themselves.  Ruby's nice  
> features make use of #reopen an exceptional circumstance, but there  
> are times where it's appropriate.

You do not make that point on the blog entry which provoked my remark. 
(I wanted to place it there but comments are closed.)

>> Btw, in 1.8 there is also $defout - I believe _that- is the stream
>> used by Kernel#puts and the like in those versions:
>>
>> 08:13:00 ~$ ruby -r stringio -e 'puts 1; $defout=StringIO.new; puts 2'
>> 1
>> -e:1: warning: $defout is obsolete; use $stdout instead
> 
> This warning says otherwise.

Please do not let yourself be distracted by the warning.  The crucial 
point is that after $defout has been reassigned the "2" does not appear 
any more on the screen => this is the object which is used by #puts.

>  They happen to be the same object though:
> 
> $ ruby -e 'p $stdout.object_id, $defout.object_id'
> 97260
> 97260

Yes - until you reassign any of them. :-)

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/