Question

I’ve just inherited this code in PHP which seems to do some kind of web service call to googles api. I’m not quite an expert on PHP and there is a few syntax questions I have specifically relating to the following line
$soapClients = &APIlityClients::getClients();

I understand the double “::” as indicating that APIlityClients is a static class but I’m not sure what the “&” in front of APIlityClients means.

Answer 1

When you use an ampersand in front of a variable in PHP, you’re creating a reference to that variable.

$foo = 'bar';
$baz = &$foo;

echo $foo //bar
echo $baz //bar

$foo = 'foobazbar';
echo $foo //foobazbar
echo $baz //foobazbar

Prior to PHP5, when you created an object from a class in PHP, that object would be passed into other variables by value. The object was NOT a reference, as is standard in most other object oriented (Java, C#, etc.) languages.

However, by instantiating a class with an ampersand in front of it, you could create a reference to the returned object, and it would behave like an object in other languages. This was a common technique prior to PHP5 to achieve OOP like effects and/or improve performance.