(PHP 7, PHP 8)
ReflectionFunctionAbstract::hasReturnType — Checks if the function has a specified return type
Checks whether the reflected function has a return type specified.
此函數沒(méi)有參數。
Returns true if the function is a specified return type, otherwise false.
示例 #1 ReflectionFunctionAbstract::hasReturnType() example
<?php
function to_int($param) : int {
return (int) $param;
}
$reflection1 = new ReflectionFunction('to_int');
var_dump($reflection1->hasReturnType());
以上例程會(huì )輸出：
bool(true)
示例 #2 Usage on built-in functions
<?php
$reflection2 = new ReflectionFunction('array_merge');
var_dump($reflection2->hasReturnType());
以上例程會(huì )輸出：
bool(false)
This is because many internal functions do not have types specified for their parameters or return values. It is therefore best to avoid using this method on built-in functions.