嵌套include_once问题

Question

Here is my directory tree:

• /
  • index.php
• include/
  • functions.php
  • head.php
  • connect.php
• sub/
  • index.php

In my head.php and connect.php both have:

include_once 'include/functions.php';

My index.php in the root folder includes these two: head.php and connect.php like this:

include_once 'include/connect.php';
include_once 'include/head.php;'

However, when my index.php in sub/ includes functions.php and head.php, they would fail to also include functions.php. Here's how I included in the sub/index.php:

include_once '../include/connect.php';
include_once '../include/head.php';

If I change in the head.php and connect.php to: include_once '../include/functions.php';

The sub/index.php would include everything normally but the index.php in the root would fail to load the functions.php.

How can I fix this?

PHP version: 5.2.*

Answer 1

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The Error

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Include statement error in head.php and connect.php

include_once 'include/functions.php';

---

The Fix

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include_once 'functions.php';

OR

include_once __DIR__ . 'functions.php'; //PHP 5.3 or higher

OR

include_once dirname(__FILE__) . 'functions.php'; //PHP 5.2 or lower

---

The Reason

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head.php and connect.php are located in the same folder as functions.php

As suggested by @Schleis, using __DIR__ (PHP 5.3+) or dirname(__FILE__); (PHP 5.2-) will allow for relative file includes.