$re = '/<SW-VARIABLE>\s*<SHORT-NAME>(?P<sn>[^<]*?)</SHORT-NAME>.*?<SW-ARRAYSIZE>\s*<VF>(?P<vf>[^<]*?)</VF>\s*</SW-ARRAYSIZE>.*?<(?:/(?!<SW-VARIABLE>)[^/]*?)SW-VARIABLE>/sm';
$str = ' <SW-VARIABLE>
<SHORT-NAME>abc</SHORT-NAME>
<CATEGORY>VALUE</CATEGORY>
<SW-ARRAYSIZE>
<VF>4</VF>
</SW-ARRAYSIZE>
<SW-DATA-DEF-PROPS>
cde
</SW-DATA-DEF-PROPS>
</SW-VARIABLE>
<SW-VARIABLE>
<SHORT-NAME>def</SHORT-NAME>
<CATEGORY>VALUE</CATEGORY>
<SW-ARRAYSIZE>
<VF>8</VF>
</SW-ARRAYSIZE>
<SW-DATA-DEF-PROPS>
<HELLO>dsfadsf </HELLO>
<NO>itis</NO>
</SW-DATA-DEF-PROPS>
</SW-VARIABLE>';
preg_match_all($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