Re: [PATCH] Don't error out if stdin/stdout/stderr was already closed.

[James Youngman]

On Sun, Apr 11, 2010 at 1:06 PM, Jim Meyering <address@hidden> wrote:
> James Youngman wrote:
>> * lib/closeout.c (close_stdout): Don't signal an error closing
>> stdout or stderr if it was already closed.
>> * lib/closein.c (close_stdin): Don't signal an error closing stdin
>> if it was already closed.
>> * lib/close-stream.c (close_stream): Make boolean variables const
>> to document the fact that we set but do not change them.
>
> Hi James,
>
> Thanks for the patch, but why do you want to do that?
>
> Here are examples showing why we should keep the existing behavior.
> Currently, cp diagnoses failure to write verbose output to a closed stdout:
>
>    $ cp --verbose a b >&-
>    cp: write error: Bad file descriptor

Right.   Here, potentially-useful data has been lost (at the
instruction of the user, in this case).   The diagnostic is going to
be useful for some programs.  Gnulib, being a library, has no way to
know when the diagnostic will not be useful.

However, while a failure to flush data should be diagnosed, I think
that if no output data would in fact be lost, there is no problem and
a diagnostic shouldn't be issued.   If you agree, I could submit a
modified patch.

The use case I have in mind is a somewhat contrived example

$  ./find/oldfind doc -mindepth 1 -ok echo {} \;  <&-
< echo ... doc/Makefile > ? ./find/oldfind: error closing file
$

James.