What are the References in PHP?

[Flaco]

Hello friends,
I have done some basic things with the PHP programming language but I am not expert in that. You guys really helped me last time, so I thought to post my doubts here again instead of searching it on web. When I went through the term references, I was blank after that, since I don't know anything about the references.!! Please explain me what are the References in PHP? Any coding related to the same topic would be very grateful.! Expecting some solutions faster.!!

[Allan.d]

You can access the same variable content by different names with the help of References. References in PHP are simpler than the related mechanism found in C and C++. C and C++ use pointers. But you can say that they are not like C pointers, because you cannot perform pointer arithmetic using them. When you try to compare the C++ to the PHP programming language then I would say that using PHP for the references is much better. By using references, you can refer or point to the same data using different variables.

[MELTRONICS]

One thing you will have to keep in mind that in PHP, variable name and variable content are different, so the same content can have different names. You can also do hardlinking in Unix filesystem, by using the references. You can create a reference by assigning a variable with the reference operator just like I have explained below :

$x = "data";
$z =& $x; 

A reference in PHP is a variable that "references" the contents of another variable.

[Deabelos]

You can pass a variable by reference to a function so the function can modify the variable. The syntax is as follows :

<?php
function call(&$var)
{
    $var++;
}

$a=5;
call($a);
?>

[Praetor]

For passing the reference correctly, functions definition alone are enough. The following things can be passed by reference:

1. Variables
2. New statements
3. References which are returned from functions

See the following example for explanation :

<?php
function call(&$var)
{
    $var++;
}
function &bar()
{
    $a = 7;
    return $a;
}
call(bar());
?>

[Katty]

The main thing to keep in mind is that references are not pointers. You can perform three basic operations using references. They are described as follows :

• assigning by reference
• passing by reference
• returning by reference.

PHP references allow you to make two variables refer to the same content. If you assign, pass, or return an undefined variable by reference, it will get created. The following sample of coding explains the same :

<?php
function call(&$var) { }

call($a); 

$b = array();
call($b['b']);
var_dump(array_key_exists('b', $b));

$c = new StdClass;
call($c->d);
var_dump(property_exists($c, 'd')); 
?>