isset(), undefined variables, and null

Is there a way to tell whether accessing a variable will
result in an "Undefined variable" E_NOTICE? isset() almost
does this, but it also returns false if a variable is set to
null:

$SetNonNull = 0;
$SetNull = null;
var_dump(isset($SetNonNull)); // bool(true)
$Junk = $SetNonNull; // No error, as predicted by isset().
var_dump(isset($NotSet)); // bool(false)
$Junk = $NotSet; // Raises an E_NOTICE, as predicted by isset().
var_dump(isset($SetNull)); // bool(false)
$Junk = $SetNull; // No error -- how to predict?

I realize I could do this by e.g., doing @$Var and checking
afterwards using $php_errormsg or a custom error handler;
I'm hoping for something less klugey.

Thanks,

--
Aaron
http://arundelo.com/

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