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Returning by-reference is useful when you want to use a function to find which variable a reference should be bound to. Do not use return-by-reference to increase performance, the engine is smart enough to optimize this on its own. Only return references when you have a valid technical reason to do it! To return references, use this syntax:
<?php
function &find_var($param)
{
/* ...code... */
return $found_var;
}
$foo =& find_var($bar);
$foo->x = 2;
?>
In this example, the property of the object returned by the
find_var
function would be set, not the
copy, as it would be without using reference syntax.
Unlike parameter passing, here you have to use
&
in both places - to indicate that you
return by-reference, not a copy as usual, and to indicate that
reference binding, rather than usual assignment, should be done
for $foo
.
If you try to return a reference from a function with the syntax:
return ($found_var);
this will not
work as you are attempting to return the result of an
expression, and not a variable, by reference. You can
only return variables by reference from a function - nothing else.
E_NOTICE
error is issued since PHP 4.4.0 and PHP
5.1.0 if the code tries to return a dynamic expression or a result of the
new
operator.