preg_match_all需要3个参数？

Here is my code:

$myText = "@koraytugaykoray@";
$mypattern = "@k.*y@";
echo "<br />";

preg_match_all($mypattern, $myText);

I am getting:

Warning: preg_match_all() expects at least 3 parameters, 2 given in C:\DocumentRoot\Framework\index.php on line 12

But according to: http://php.net/manual/en/function.preg-match-all.php , this should be fine?

In versions before 5.4.0 the 3rd argument to preg_match_all() was not optional:

5.4.0 The matches parameter became optional.

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