(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.
此函数没有参数。
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());以上示例会输出：
bool(true)
示例 #2 Usage on built-in functions
<?php
$reflection2 = new ReflectionFunction('array_merge');
var_dump($reflection2->hasReturnType());以上示例会输出：
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.