PHP references allow you to make two variables to refer
to the same content. Meaning, when you do:
注: $a and $b are completely equal here, that's not $a is pointing to $b or vice versa, that's $a and $b pointing to the same place.
The same syntax can be used with functions, that return
references, and with new operator
(in PHP 4.0.4 and later):
注: Not using the operator causes a copy of the object to be made. If you use $this in the class it will operate on the current instance of the class. The assignment without will copy the instance (i.e. the object) and $this will operate on the copy, which is not always what is desired. Usually you want to have a single instance to work with, due to performance and memory consumption issues.
While you can use the @ operator to mute any errors in the constructor when using it as @new, this does not work when using the new statement. This is a limitation of the Zend Engine and will therefore result in a parser error.
The second thing references do is to pass variables
by-reference. This is done by making a local variable in a
function and a variable in the calling scope reference to the
same content. Example:
The third thing reference can do is return by
reference.