php - 使用空不能提供正确的结果

Question

有人能告诉我为什么当 session 显然有值时我能够在这个 block 内回显吗？

$_SESSION['test']['testing'] = 'hgkjhg';
echo $_SESSION['test']['testing']; // Produces hgkjhg (Clearly not empty)

if(empty($_SESSION['test']['testing'])){
echo 'Hello'; // This echoes and to me, shouldn't
}

Answer 1

真正的答案是关于 session_start .不像session_register ，直接分配给 $_SESSION 不会自动调用 session_start。

直接来自 session_register() 的 PHP 手册

If session_start() was not called before this function is called, an implicit call to session_start() with no parameters will be made. $_SESSION does not mimic this behavior and requires session_start()