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Re: How to dup a FILE*

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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]).

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Thread

How to dup a FILE* Josef Moellers <josef.moellers@ts.fujitsu.com> - 2011-12-06 09:51 +0100
  Re: How to dup a FILE* Richard Kettlewell <rjk@greenend.org.uk> - 2011-12-06 09:16 +0000
    Re: How to dup a FILE* Josef Moellers <josef.moellers@ts.fujitsu.com> - 2011-12-06 10:41 +0100
  Re: How to dup a FILE* Jasen Betts <jasen@xnet.co.nz> - 2011-12-06 13:28 +0000
    Re: How to dup a FILE* Josef Moellers <josef.moellers@ts.fujitsu.com> - 2011-12-06 16:57 +0100
  Re: How to dup a FILE* David W Noon <dwnoon@spamtrap.ntlworld.com> - 2011-12-06 19:53 +0000
    Re: How to dup a FILE* Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-12-06 20:38 +0000
      Re: How to dup a FILE* Richard Kettlewell <rjk@greenend.org.uk> - 2011-12-06 22:03 +0000
      Re: How to dup a FILE* David W Noon <dwnoon@spamtrap.ntlworld.com> - 2011-12-06 21:46 +0000
        Re: How to dup a FILE* Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-12-07 17:52 +0000

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