How to Start a PHP Function with an Ampersand

In PHP, an ampersand (<kbd class="highlighted">&</kbd>) is placed before the function name to return a reference to a variable instead of its value. Returning by reference is useful when you need a function to bind directly to a specific variable.

An Example of Returning a Reference

To illustrate, let’s consider a detailed example of using an ampersand to return a reference from a PHP function.

This allows you to modify the original object property directly, rather than working with a copy.

Unlike passing parameters by reference, returning by reference requires the ampersand in both the function definition and the assignment statement.

The example will look as follows:

php use ampersand to return by reference

<?php

class pupil
{
  public $value = 42;

  public function &getValue()
  {
    return $this->value;
  }
}

$obj = new pupil();

// $myValue is a reference to
// $obj->value, which is 42.
$myValue = &$obj->getValue();
$obj->value = 2;

// Printing the new value of
// $obj->value, i.e. 2.
echo $myValue;

?>

php use ampersand to return by reference, output

2

References and Ampersands in PHP

References allow two variables to point to the same content.

In other words, a variable holds a reference to its content rather than being the content itself.

Passing by reference allows two variables to share the same content under different names. To create a reference, place an ampersand before the variable name.