use strict;
use FileHandle;
use IO::Compress::Gzip;

my $unicode_string = "Smiley Face: \x{263A}\n";

writefile({
    'filename'  => "/tmp/out",
    'gzip'      => 0,
    'data'      => $unicode_string,
});

writefile({
    'filename'  => "/tmp/out.gz",
    'gzip'      => 1,
    'data'      => $unicode_string,
});

sub writefile {
    my($opts) = @_;

    my $fh = ($opts->{'gzip'}) ?
        IO::Compress::Gzip->new(
            FileHandle->new("> $opts->{'filename'}"),
        ) :
        FileHandle->new("> $opts->{'filename'}");

    binmode($fh, ':utf8');

    print $fh $opts->{'data'};
    $fh->close;
}

__DATA__