Fellow monks,

I am experiencing some inconsistent behavior with tied filehandles between perl 5.6.1 and 5.8.3 (ActiveState Perl).
Background Info: I'm looking to carefully insert a few lines of perl code into a bunch of existing scripts to make sure everything printed to the 'screen' (stdout, stderr, stdin) also gets recorded in a logfile.
Constraints: I'm hoping to avoid having to change a zillion 'print' statements to do this. I have to be careful not to depend on CPAN packages as this will introduce additional administrative overhead. I'm hoping to have this working on both 5.6 and 5.8.
The Problem: In 5.6.1 output to the screen does not seem to come out in the expected 'sequence' and nothing is printed to the logfile after the tie.

Is this a bug in 5.6? Is there a better way to write this that may sidestep whatever issue there might be?

Code: 
#! perl -w

use strict;
$| = 1;

print "$0 | start | " . localtime() . "\n";

print STDOUT "This is STDOUT\n";
print "Now ask for STDIN: ";
my $input = <STDIN>;
chomp($input);
print "Input : " . $input . "\n";

print "Now let's mess with things...\n";

my $logfile = "./logfile.log";
open( STDOUT_TOO, ">&STDOUT" ) or die "Cannot dup STDOUT handle to STD
+OUT_TOO: $!";
open( LOGFILE, ">$logfile" ) or die "Cannot open $logfile for output: 
+$!";
tie *STDOUT, 'MyMultiplex', \*STDOUT_TOO, \*LOGFILE;

print "And let's see the effects...\n";

print STDOUT "This is STDOUT\n";
print "Now ask for STDIN: ";
$input = <STDIN>;
chomp($input);
print "Input : " . $input . "\n";

print "$0 | end | " . localtime() . "\n";

package MyMultiplex;

sub TIEHANDLE { my $obj = shift; bless [ @_ ], $obj; }

sub PRINT { my $self = shift; print $_ $_[0] for @$self; }

[download]


Output:
- 5.6 
H:\Developer\deploysystem\src>perl scratch.pl
scratch.pl | start | Wed Jun 30 12:13:45 2004
This is STDOUT
Now ask for STDIN: this is 5.6
Input : this is 5.6
Now let's mess with things...
'mess with things' printed out of sequence
And let's see the effects...
This is STDOUT
Now ask for STDIN: Input : 'mess with things' printed out of sequence
scratch.pl | end | Wed Jun 30 12:14:06 2004

[download]


- 5.8 
H:\Developer\deploysystem\src>perl scratch.pl
scratch.pl | start | Wed Jun 30 12:15:07 2004
This is STDOUT
Now ask for STDIN: this is 5.8
Input : this is 5.8
Now let's mess with things...
And let's see the effects...
This is STDOUT
Now ask for STDIN: it works on my machine!
Input : it works on my machine!
scratch.pl | end | Wed Jun 30 12:15:18 2004

[download]

edit: added another <readmore>

In reply to tied filehandle behaviour 5.6 vs 5.8 by medellre

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