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From: Rainer Weikusat <rweikusat@mssgmbh.com>
Newsgroups: comp.os.linux.development.apps
Subject: Re: How to dup a FILE*
Date: Tue, 06 Dec 2011 20:38:47 +0000
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David W Noon <dwnoon@spamtrap.ntlworld.com> writes:
> On Tue, 06 Dec 2011 09:51:43 +0100, Josef Moellers wrote about How to
> dup a FILE*:
>
>>I need to juggle with stderr: redirecting it from one file to another
>>and back.
> [snip]
>
> I think you're over-complicating things here.  After all, stderr is
> simply a pointer.  So, cache the old pointer; open a new file stream
> stored in stderr; fclose(stderr) when done; reinstate the original
> pointer.

That's a thoroughly stupid idea because it won't affect output to
'standard error filedescriptor' which doesn't go through the stderr
stream *and* while the glibc documentation claims that this should
work, it actually doesn't (or at least didn't for some random version
where I tried this about ten years ago -- only to be told that I
"should use freopen instead" by Ulrich Drepper [which I couldn't do
because I was trying to divert the output to a socket]).