$re = '/var (.*?)=function.*ZZZ/';
$str = 'var some_fnc1=function(a,b,c){var a = 1+1;b=a++;c=b+a;}var some_fnc2=function(a){some();and_one(a) return false;}var some_fnc3=function(z,x,y){new AnySome(/sdds/i);var ZZZ=1;}var some_fnc4=function(ololo){var b = 1+1;b=z++;c=b+a;}';
preg_match_all($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