Checking To See If Something Is Not An Integer

I put together this:

//Make Sure $qty is NOT blank before checking if it is a number	if (!empty($item_1_qty)) {//not empty			}	if (intval($item_1_qty) !== $item_1_qty){			//item 1 qty is not a whole number			$redirect_to = 'order_form.php?error=6';				header("Location: $redirect_to");			exit();		}

But I get my error message coming no matter whether it is an integer or not.
Edited November 20, 2006 by ginginca (see edit history)

if (intval($item_1_qty) !== $item_1_qty){

Where is the value for the $item_1_qty coming from? if it is coming from a form, it may be cast as a string and the php.net site lists a series of examples which you might be interested in reviewing.
http://us3.php.net/manual/en/function.intval.php

I put together this:

//Make Sure $qty is NOT blank before checking if it is a number	if (!empty($item_1_qty)) {//not empty			}	if (intval($item_1_qty) !== $item_1_qty){			//item 1 qty is not a whole number			$redirect_to = 'order_form.php?error=6';				header("Location: $redirect_to");			exit();		}

But I get my error message coming no matter whether it is an integer or not.

If your variable is coming from a form i reccomend you to cast it before you use it, its simple:

$item_1_qty = (int) $_POST['item_1_qty'];

Also take a look to the is_numeric() php function, because it is recommended to use it with variables that are submited by a form.

Best regards,

PHP has a function called is_int() to test if parameter is integer. Why not just use that?

..and why not better to use a function is_numeric() to see if the variable is a number or a numeric string, or you really need it to be integer.. But if so, the above replies have said enough.