【转载】PHP使用empty检查函数返回结果时报Fatal error: Can't use function return value in write context的问题

Fatal error: Can't use function return value in write context

<?php
echo empty(strlen('be-evil.org'));

Note: empty() only checks variables as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).

empty()

<?php

$length = strlen('be-evil.org');

echo empty($length);