$re = '/\(generic:(?<Field>[^\)]*)\)\(/';
$str = 'String = This is the string (generic:ggmail.com)(3245612)
= This is the string (generic:abcdexadsfsdf.cc)(1232143)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php