preg_replace( mixed $pattern, mixed $replacement, mixed $subject [, int $limit=-1 [, int &$count]]] )

preg_replace ( "", "", "", -1, 0 );

returned:
count: 0
Pattern *This can be an array of strings, but not here replacement *This can be an array of strings, but not here Subject *This can be an array of strings, but not here limit (optional) count (optional)