&$variable

[raku]

Hi,

 

Does anyone know what an "&" sign before a variable does?

 

&$variable

 

Thanks!

[Fadion]

From the manual:

 

PHP also offers another way to assign values to variables: assign by reference. This means that the new variable simply references (in other words, "becomes an alias for" or "points to") the original variable. Changes to the new variable affect the original, and vice versa. 

To assign by reference, simply prepend an ampersand (&) to the beginning of the variable which is being assigned (the source variable).

 

If it doesnt make things clear, go to this page and take a look at the examples.

[Barand]

Without the "&" the value of $x is passed to the function

<?php  
$x = 0;

function foo ($var)                              // pass by value
{
    $var += 1;
    return $var;
}

echo $x, '<br>';
echo foo ($x), '<br>'; 
echo $x, '<br>';

?>

 

With the "&", variable $x is passed by reference, so the variable inside the function is the same one as that outside

<?php  
$x = 0;

function bar (&$var)                               // pass by reference
{
    $var += 1;
    return $var;
}

echo $x, '<br>';
echo bar ($x), '<br>'; 
echo $x, '<br>';                                   // $x is incremented

?>