From: Rudolf Polzer <denshimeiru-sapmctacher@...>
Date: 2003-09-19T20:17:26+09:00
Subject: Re: closing stderr

Scripsit illa aut ille �Robert Klemme� <bob.news@gmx.net>:
> "Rudolf Polzer" <denshimeiru-sapmctacher@durchnull.de> schrieb im Newsbeitrag
> news:slrnbmjng5.kqp.denshimeiru-sapmctacher@message-id.durchnull.ath.cx...
> > Scripsit illa aut ille �Robert Klemme� <bob.news@gmx.net>:
> > > "Michael Garriss" <mgarriss@earthlink.net> schrieb im Newsbeitrag news:3F69D414.70008@earthlink.net...
> > > > I would like to prevent some output that is going to stderr during a
> > > > call to a third party lib just during that call.  My first guess was:
> > > >
> > > > STDERR.close_write
> > > > ThirdPartyLib::call_some_annoying_function
> > > > STDERR.????
> > > >
> > > > I guess you can see my problem.  Can anyone give me a lead on this?
> > [...]
> > > $stderr = StringIO.new
> > > STDERR = $stderr
> >
> > Are you sure it occupies file descriptor 2 (which external libraries
> > normally use)?
> >
> >   def without_stderr(&block)
> >     save = $stderr.dup()
> >     $stderr.close() # this will affect STDERR, too.
> >     begin
> >       yield
> >     ensure
> >       $stderr = save.dup()
> >       # SIDE EFFECT: the file descriptor STDERR points to will be valid again
> >     end
> >   end
> >
> > However, this routine assumes that all file descriptors before
> > $stderr are used. This is the case unless $stdin or $stdout have
> > been closed. Is there something like dup2() in Ruby?
> 
> This routine has a totally different problem: closing $stderr make the lib
> function abort because it will get an exception on writing to $stderr.
> $stderr has to be something that is open.

Then use the StringIO trick from the other posting.

I thought about an external library which is an interface to an
existing C library which writes to stderr (file descriptor 2).


-- 
The only thing that Babelfish is good at is proving that Vogons are
great poets.
                                   Josef 'Jupp' Schugt in japan.anime.evangelion