$re = 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)*\](?:(?:\r\n)?[\t])*))*|(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|"(?:[^\"\r\\\\]|\\\\.|(?:(?:\r\n)?[\t]))*"(?:(?:\r\n)?[\t])*)*\<(?:(?:\r\n)?[\t])*(?:@(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*)(?:\.(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*))*(?:,@(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*)(?:\.(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*))*)*:(?:(?:\r\n)?[\t])*)?(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|"(?:[^\"\r\\\\]|\\\\.|(?:(?:\r\n)?[\t]))*"(?:(?:\r\n)?[\t])*)(?:\.(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|"(?:[^\"\r\\\\]|\\\\.|(?:(?:\r\n)?[\t]))*"(?:(?:\r\n)?[\t])*))*@(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*)(?:\.(?:(?:\r\n)?[\t])*(?:[^()<>@,;:\\\\".\[\]\000-\031]+(?:(?:(?:\r\n)?[\t])+|\Z|(?=[\["()<>@,;:\\\\".\[\]]))|\[([^\[\]\r\\\\]|\\\\.)*\](?:(?:\r\n)?[\t])*))*\>(?:(?:\r\n)?[\t])*))*)?;\s*)/';
$str = '';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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