Notice: Undefined variable:

[Whenry270818]

The php script is

<?php
$testing;
echo "is null? " .is_null($testing);
echo "<br/>";
$testing = 5;
echo "is integer? " .is_int($testing);
?>

the output I get is

Notice: Undefined variable: testing in /Library/WebServer/Documents/test.php on line 3
is null? 1
is integer? 1

I understand that $testing is undefined when used in line 3, but why is it telling me..?

OS X 10.5.5
PHP 5.2.6

[NogDog]

It's raising a notice-level error message because you are trying to perform an operation on a variable that is not defined. It is suggesting that perhaps you have some sort of logic error or simply have mistyped the variable name. The notice does not stop processing and could be suppressed if you wanted, though it's generally better to somehow initialize it so that there is no ambiguity:

<?php
if(!isset($testing))
{
   $testing = null;
}
echo "is null? " .is_null($testing);
echo "<br/>";
$testing = 5;
echo "is integer? " .is_int($testing);
?>

[Whenry270818]

Thank you NogDog, I understand now.