PHP中require_once的范围是什么? [英] What is the scope of require_once in PHP?

问题描述

一个简单的问题:require_once的范围是全局的吗?

Simple question: Is the scope of require_once global?

例如:

<?PHP

require_once('baz.php');

// do some stuff
foo ($bar);

function foo($bar) {
    require_once('baz.php');
    // do different stuff
}

?>

调用foo时，会重新解析baz.php吗?还是依赖于主php文件中已经需要的文件(类似于对于相同的include文件连续两次调用require_once )?

When foo is called, does it re-parse baz.php? Or does it rely on the already required file from the main php file (analagous to calling require_once twice consecutively for the same include file)?

我以前见过这个线程，但是并没有完全回答这个问题:

I saw this thread before, but it didn't quite answer the question:

应该require_once某些file.php" ;出现在文件顶部以外的任何地方?

感谢您的帮助！

推荐答案

require_once()基本上依赖于物理文件来确定是否包含该文件.因此，要调用require_once()的上下文并不多，而是以前是否需要该物理文件.

require_once() basically relies on the physical file to determine whether or not it's been included. So it's not so much the context that you're calling require_once() in, it's whether or not that physical file has previously been required.

在上面的代码中，您的foo()函数将不会重新解析baz.php，因为它将与先前在顶部包含的文件相同.

In your code above, your foo() function would not re-parse baz.php, since it is going to be the same file as was previously included at the top.

但是，根据将其包含在foo()内还是将其包含在顶部，您将获得不同的结果，因为当require_once()成功执行时，作用域将适用.

However, you will get different results based on whether you included it inside foo(), or included it at the top, as the scoping will apply when require_once() does succeed.

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