PHP Call By Reference:
So, whenever you want to recieve arguments by reference, varibale must be prefixed by & symbol. It acutally makes reference to variables for calling the function. See the example below:
<?php
function add(&$x)
{
$x .= 'Call By Reference';
}
$y = ' Exanple of ';
add($y);
echo $y; //concate two string using call by reference
?>
Result will be: Exanple of Call By Reference
see another example:
<?php
function add(&$x)
{
$x--;
}
$y = 5;
add($y);
echo $y; //decrement using call by reference
?>