Question

can any one please tell me how to pass a variable as/by value?
what i did a mistake on the below code, its shows an parse error

$a = &$$b

Answer 1

While it might be a little hard to follow, your code is perfectly valid and is doing what you want it to do:

$b = 'test';
$test = 100;
$a = &$$b;
echo $a; // displays 100

You are likely getting an error because $b is not set.