ReflectionParameter::allowsNull

(PHP 5, PHP 7, PHP 8)

ReflectionParameter::allowsNull — Checks if null is allowed

说明

public ReflectionParameter::allowsNull(): bool

Checks whether the parameter allows null.

参数

此函数没有参数。

返回值

true if null is allowed, otherwise false

参见

ReflectionParameter::isOptional() - Checks if optional

改进此页面

了解如何改进此页面 • 提交拉取请求 • 报告一个错误

＋添加备注

用户贡献的备注 2 notes

down

Geoffrey LAURENT ¶

11 years ago

The allowsNull method look if arguments have a type. 
If a type is defined, null is allowed only if default value is null.

 <?php 
function myfunction ( $param ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";

?>

Result : true

<?php 
function myfunction ( stdClass $param ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";

?>

Result : false

<?php
function myfunction ( stdClass $param = null ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";
?>

Result : true

down

tuncdan dot ozdemir dot peng at gmail dot com ¶

8 months ago

Please note that `mixed` type parameter also returns true, as `null` is part of the `mixed` union.

And there does not have to be a default `null` value for `->allowsNull()` to return true.

function test (AnyType|null $param1, mixed $param2) {}

Both parameters from the function above will return true for `allowsNull()`.