Affected rows VS Matched rows

[eluser]Alexxz[/eluser]
[quote author="xwero" date="1196948000"]Have you checked the mysql driver code to see if there is a hack for this behaviour?[/quote]

What kind of hack? there is only

Code:

function affected_rows()
    {
        return @mysql_affected_rows($this->conn_id);
    }

I can't find any related methods.