open(my $fh, "<:encoding($CEF)", $qfn) or die;
while (<$fh>) {
   print("Line $. contains EM DASH\n") if /\x{2014}/;
}

##</code><code>##

# :locale doesn't work on Windows :(
use open ':std', ':encoding(cp1252)';

for my $enc (qw( Windows-1252 UTF-8 )) {
   print("$enc:\n");

   {
      open(my $fh, ">:encoding($enc)", 'data.txt') or die;
      print($fh "foo\nbar\nfoo\x{2014}bar\nmeow\n");
   }

   {
      open(my $fh, "<:encoding($enc)", 'data.txt') or die;
      while (<$fh>) {
         print;
         print("Line $. contains EM DASH\n") if /\x{2014}/;
      }
   }

   print("\n");
}