This is perl 5.8.6/AS811 on XP:

c:\test>perl
use File::Temp qw( tempfile );
use File::Spec qw( devnull );
$|=1;

my $code =<<'CODE';
  $|=1;
  print "ABC\n";
  print STDERR "012\n";
  print "IJK\n";
  print STDERR "345\n";
  print "XYZ\n";
  print STDERR "678\n";
CODE

# create a temporary perl script file
my ($fh1, $scriptname) = tempfile( 'yap_XXXX', SUFFIX => '.pl');
print {$fh1} $code;
close( $fh1 );

my $perl = $^X;
my $devnull = File::Spec->devnull;
print "No redirect: \n";
print qx{ $perl $scriptname }, "\n";
print "Redirect errors to devnull: \n";
print qx{ $perl $scriptname 2>$devnull }, "\n";
print "Redirect merging stderr and stdout: \n";
print qx{ $perl $scriptname 2>&1 }, "\n";
^Z
No redirect:
012
345
678
ABC
IJK
XYZ

Redirect errors to devnull:
ABC
IJK
XYZ

Redirect merging stderr and stdout:
ABC
012
IJK
345
XYZ
678
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