What does an @ sign before a VARIABLE do?

Hey all, In the PHOBUILDER tutorial on sessions the sample code has a @ sign before some of the variable names.. like: if (@$userid && @$password) { $res = @mysql_query("SELECT userid FROM users WHERE userid='$userid' AND password='$password'"); if(@mysql_num_rows($res) != 0) {

    $verified_user = $userid;
    session_register("verified_user");

} } I've never seen that before and am curious what it does. I've seen it before function calls, but never before variables. Thanks! -Mike

           -=- Mike Flynn - Burlington, VT -=-

mike@mikeflynn.net http://www.mikeflynn.net/ * Give blood *