How to get the first subdomain with PHP?

Question

I have a static domain of dev.example.com with wildcard subdomains like so *.dev.example.com.

I need to detect the name of the current wild

Answer 1

$domain = 'sub.dev.example.com';
$tmp = explode('.', $domain);
$subdomain = current($tmp);
print($subdomain);     // prints "sub"