Quick Question

[Hate]

Hi, I've seen code like this multiple times, but I don't really know what it means.

 

function funcName(&$something) {
    // whatever
}

 

What exactly does the "&" do before the variable?

[Pikachu2000]

These explain it pretty well. (Better than I could, at least)

 

http://www.whypad.com/posts/php-what-is-the-ampersand-preceding-variables/193/

http://www.phpreferencebook.com/samples/php-pass-by-reference/

[Andy-H]

When you pass a variable to a function, it's value is copied to a variable in the local scope of the function, so in order for the functions effect to take place in global scope, you would have to return the variable and assign it as an rvalue to a variable in global scope.

 

The & operator passes a reference of the variables memory location to the function, so any changes made to that variable within the scope of the function, take effect on the same variable in global scope.

 

Try this:

 

$var = 'Hello';

echo 'Global scope $var: ' . $var . '<br /><br />';
function world(&$var)
{
   $var .= ' World!';
}

function wrongWorld($var)
{
   $var .= ' World!';
   echo 'Function scope $var: ' . $var . '<br />';
}

wrongWorld($var);
echo 'Global scope $var: ' . $var . '<br />';

word($var);
echo 'Global scope $var after reference: ' . $var . '<br />';