How do I know the country of a particular IP?

Well, what I wanted to know was the country of a particular IP, I've already used the geoiplocation of PHP, however when I start to run on my server it appears to me the following error:

Fatal error: Call to undefined function geoip_country_name_by_name() in C:\Program Files\VertrigoServ\www\ExtraGrana\new\testando.php on line 4

When I put it on my cpanel server, the following message appears: The "url from my site" page is not working. "

<?php


$country = geoip_country_name_by_name('www.google.com');


echo $country;
?>

What's wrong with this code?

Thank you.