����ֵ

ֵͨ��ʹ�ÿ�ѡ�ķ�����䷵�ء����Է��ذ�������Ͷ�����������͡���������������ֹ���������У����ҽ�����Ȩ���ص��øú����Ĵ����С�������Ϣ�� return��

Note:

���ʡ���� return���򷵻�ֵΪ NULL��

return ��ʹ��

Example #1 return ��ʹ��

<?php
function square($num)
{
    return $num * $num;
}
echo square(4);   // outputs '16'.
?>

�������ܷ��ض��ֵ��������ͨ������һ���������õ����Ƶ�Ч����

Example #2 ����һ�������Եõ��������ֵ

<?php
function small_numbers()
{
    return array (0, 1, 2);
}
list ($zero, $one, $two) = small_numbers();
?>

�Ӻ�������һ�����ã������ں���������ָ�ɷ���ֵ��һ������ʱ��ʹ����������� &��

Example #3 �Ӻ�������һ������

<?php
function &returns_reference()
{
    return $someref;
}

$newref =& returns_reference();
?>

�й����õĸ�����Ϣ, ��鿴���õĽ�����

Return type declarations

PHP 7 adds support for return type declarations. Similarly to argument type declarations, return type declarations specify the type of the value that will be returned from a function. The same types are available for return type declarations as are available for argument type declarations.

Strict typing also has an effect on return type declarations. In the default weak mode, returned values will be coerced to the correct type if they are not already of that type. In strong mode, the returned value must be of the correct type, otherwise a TypeError will be thrown.

Note:

When overriding a parent method, the child's method must match any return type declaration on the parent. If the parent doesn't define a return type, then the child method may do so.

����

Example #4 Basic return type declaration

<?php
function sum($a, $b): float {
    return $a + $b;
}

// Note that a float will be returned.
var_dump(sum(1, 2));
?>

�������̻������

float(3)

Example #5 Strict mode in action

<?php
declare(strict_types=1);

function sum($a, $b): int {
    return $a + $b;
}

var_dump(sum(1, 2));
var_dump(sum(1, 2.5));
?>

�������̻������

int(3)

Fatal error: Uncaught TypeError: Return value of sum() must be of the type integer, float returned in - on line 5 in -:5
Stack trace:
#0 -(9): sum(1, 2.5)
#1 {main}
  thrown in - on line 5

Example #6 Returning an object

<?php
class C {}

function getC(): C {
    return new C;
}

var_dump(getC());
?>

�������̻������

object(C)#1 (0) {
}