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Date: Sun, 21 Aug 2005 13:03:44 -0400 (EDT)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: cygwin AT cygwin DOT com
Subject: Re: Perl binmode problems when redirecting to text mounts
In-Reply-To: <Pine.GSO.4.61.0508211211150.16057@slinky.cs.nyu.edu>
Message-ID: <Pine.GSO.4.61.0508211252560.16057@slinky.cs.nyu.edu>
References: <Pine DOT GSO DOT 4 DOT 61 DOT 0508211211150 DOT 16057 AT slinky DOT cs DOT nyu DOT edu>
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On Sun, 21 Aug 2005, Igor Pechtchanski wrote:

> I'm trying to make sure our perl program works with text mounts.  In the
> course of the testing, one weird problem cropped up: binmode seems to
> have no effect on STDOUT when redirecting to a file on a text mount.
>
> The following consistently reproduces the problem for me:
>
> $ mount -m | grep text
> mount -f -u -t "c:/cygwin/tmp/text" "/tmp/text"
> $ cd /tmp/text
> $ /usr/bin/perl -e 'binmode(STDOUT);print "\n"' > PT
> $ od -c PT
> 0000000  \r  \n
> 0000002
> $
>
> I've tried various combinations of ":raw", ":perlio", etc, both directly
> and through the PERLIO variable, with no success.  The strace output
> (available upon request) seems to show that the handle is successfully
> set to binary mode, but that the write still happens in text mode.
>
> Can anyone else reproduce this?  Is there a way I can force binary mode
> on STDOUT in Perl?

On second thought, this probably has to do with *how* Perl sets binmode on
STDOUT.  The shells (I tried ash, bash, tcsh) don't seem to honor it.

BTW, the code I used is the same as that in /usr/bin/GET.pl and
/usr/bin/piconv (both break in the same way on redirection to files on
text mounts).

I know the shells can honor the O_BINARY specifier on STDOUT, since "cat"
uses this (via setmode(1, O_BINARY)).  There must be something that Perl
is doing differently.  Any ideas?
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
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ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

If there's any real truth it's that the entire multidimensional infinity
of the Universe is almost certainly being run by a bunch of maniacs. /DA

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