Writing out a decimal value as a hex string

A function to convert a decimal value to a hex string.

################################################################
# dec2hex
#   Convert dec number into hex string
###############################################################
sub dec2hex() {
    my $dec  = shift();
    my $fill = shift();

    my $fmt_string;

    if (defined($fill)){
      $fmt_string = "%0" . $fill . "X";
    } else {
      $fmt_string = "%02X";
    }
    return sprintf($fmt_string, $dec );
}

Use it as follows:

my $value = 10;
my $hex_string = dec2hex($value);
print "The decimal value $value is written like 0x$hex_string\n";
my $hex_string_long = dec2hex($value, 8);
print "The hex string can be extended with zeros: $hex_string_long\n";