is_resource
    (PHP 4 )
is_resource --       Finds whether a variable is a resource     
Description
bool 
is_resource ( mixed var)
     is_resource() returns TRUE if the variable      given by the var parameter is a       resource, otherwise it returns FALSE.     
     
| Example 1. using is_resource() | <?php
$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass');
if (!is_resource($db_link)) {
    die('Can\'t connect : ' . mysql_error());
}
 ?> | 
 | 
     
     See the documentation on the resource-type for      more information.