CGI.pm always calls binmode on STDOUT, STDERR, and STDIN, even if they already have IO layers [rt.cpan.org #57524] about cgi.pm HOT 2 CLOSED

[email protected] - 2010-05-16 21:26:09

In one of my scripts, before I load CGI.pm, I have an encoding() layer
set on STDOUT. Simply calling "use CGI;" will remove that layer, because
CGI.pm does this:

if ($needs_binmode) {
$CGI::DefaultClass->binmode(*main::STDOUT);
$CGI::DefaultClass->binmode(*main::STDIN);
$CGI::DefaultClass->binmode(*main::STDERR);
}

Thus clearing any already-pushed IO layer.

Thanks for the report. What alternative do you recommend?

Mark

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MKANAT - 2010-05-16 22:50:38

On Sun May 16 17:26:09 2010, [email protected] wrote:

Thanks for the report. What alternative do you recommend?

I'm actually not quite sure. I don't know how to check if a file handle
is already in binmode. I do know how to check if it has an encoding or
utf8 layer on it, though, which is PerlIO::get_layers(FH).

What's the purpose of setting binmode on STD* on Windows? Is it so that
it doesn't do CR->CRLF conversion? I don't know if any way to
specifically remove the :crlf layer, but if there was one, that might be
a better solution.

A simple solution that would resolve my problem would be to not call
CORE::binmode on any of the file handles if they have any non-default
layers (that is, layers other than :crlf, :unix, and :perlio).

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