Mail Archives: cygwin/2005/08/21/13:03:54
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
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