Use of & with () of function

[LPH]

Hi,

I'm looking at a function within a plugin and there is an & prior to the $.

function function_name(&$classObj ....

What does the & do? Is there a link for more information? I've been googling ...

Update: I couldn't figure out if this was a typo or had a purpose. I removed the & and the plugin appears to still be working.

 

[Bob]

Its called "Passing by Reference"

http://www.php.net/manual/en/language.references.pass.php

 

[LPH]

Thank you. Now I need to figure out if this was necessary.

 

[xf_phantom]

http://www.php.net/manual/en/language.references.whatare.php
http://www.php.net/manual/en/language.references.whatdo.php
http://www.php.net/manual/en/language.references.arent.php