is_resource

(PHP 4, PHP 5, PHP 7)

is_resource — Finds whether a variable is a resource

is_resource ( mixed $var ) : bool

Finds whether the given variable is a resource.

Returns TRUE if var is a resource, FALSE otherwise.

Example #1 is_resource() example

<?php$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass');if (!is_resource($db_link)) { die('Can\'t connect : ' . mysql_error());}?>

Note:
is_resource() is not a strict type-checking method: it will return FALSE if var is a resource variable that has been closed.

Php/docs/function.is-resource