Introduction
In PHP, a function can also be made to return a reference. This is useful to find to which variable a reference should be bound. To define a function which returns reference, prefix its name by & sign.
Example
In following example, myfunction() is defined to return by reference. It contains a static variable whose reference is returned and assigned to a global variable. Value of local static variable will also change its reference ouside is assigned with different value.
Example
<?php
function &myfunction(){
static $x=10;
echo "x Inside function: ",$x,"\n";
return $x;
}
$a=&myfunction(); //contains reference to 4x in function
echo "returned by reference: ", $a, "\n";
$a=$a+10; //increments variable inside function too
$a=&myfunction();
?>Output
This example gives following output
x Inside function: 10 returned by reference: 10 x Inside function: 20
method returning reference
A class can also have a method that is able to return reference. This enables chenging value of private instance variable from outside the class
Example
<?php
class myclass{
private $val;
function __construct($x){
$this->val=$x;
}
function &getbyref(){
return $this->val;
}
function getbyval(){
return $this->val;
}
}
$a=new myclass(10);
$b=&$a->getbyref();
$b=100;
echo "Value of private property: ", $a->getbyval();
?>Output
Result of above script is as follows
Value of private property: 100