use strict;
use warnings;

use Encode;
use File::BOM qw(:all);

use open IN => ':via(File::BOM)';

my $enc = "UCS-2";
my $str = "\x{ABCD} a b c d";
my $buf = $enc2bom{$enc} . encode($enc, $str);

open(my $FH, "<", \$buf) or die $!;
my $read = <$FH>;

print($read eq $str ? "match" : "no match", "\n");

__END__
match