Passing by Reference
You can pass variable to function by reference, so that function could modify its arguments. The sytax is as follows:
function foo (&$var) {
$var++;
}
$a=5;
foo ($a);
// $a is 6 here
Following things can be passed by reference:
- Variable, i.e. foo($a)
- New statement, i.e. foo(new foobar())
-
Reference, returned from a function, i.e.:
function &bar()
{
$a = 5;
return $a;
}
foo(bar());
Any other expression should not be passed by reference, as the result is undefined. For example, the following examples of passing by reference are invalid:
function bar() // Note the missing &
{
$a = 5;
return $a;
}
foo(bar));
foo($a = 5) // Expression, not variable
foo(5) // Constant, not variable