open(my $fh, '<', $filename);
 binmode($fh);

##</code><code>##

open(my $fh, "<:raw:perlio", $file);

# read first few bytes for a BOM or ASCII in utf(16|32)
#  to determine encoding

binmode $fh, ":encoding($encoding)"

##</code><code>##

open $fh, "<", $^X or die;
binmode $fh;
print "1: ", join(' ', PerlIO::get_layers($fh, details => 1)), "\n";
close $fh;

open $fh, "<:raw:perlio", $^X or die;
print "2: ", join(' ', PerlIO::get_layers($fh, details => 1)), "\n";
close $fh;


##</code><code>##

1: unix  4195328 crlf  4195328
2: unix  4195328 perlio  4195328