Daniel Brown wrote:
> On Wed, Jan 21, 2009 at 20:27, Jack Bates <ms419@xxxxxxxxxxxxxx> wrote:
>> How can I tell the difference between a variable whose value is null and
>> a variable which is not set?
>
> Unfortunately, in PHP - like other languages - you can't.
>
> A variable is considered to be null if:
> * it has been assigned the constant NULL.
> * it has not been set to any value yet.
> * it has been unset().
>
I'm not in a position to test right now, but using Dan's logic I would
turn it around and test for isset first and then is_null. This makes
sense to me, but maybe it is flawed:
if (isset($var) && is_null($var)) {
echo "$var is set and is null";
}
Or maybe a function to return is the $var === null:
function eq_null(&$var)
{
return (isset($var) && is_null($var)) ? true : false;
}
--
Thanks!
-Shawn
http://www.spidean.com
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