Why include __DIR__ in the require_once?

早过忘川 提交于 2019-11-30 08:28:45

PHP scripts run relative to the current path (result of getcwd()), not to the path of their own file. Using __DIR__ forces the include to happen relative to their own path.

To demonstrate, create the following files (and directories):

- file1.php
- dir/
   - file2.php
   - file3.php

If file2.php includes file3.php like this:

include `file3.php`.

It will work fine if you call file2.php directly. However, if file1.php includes file2.php, the current directory (getcwd()), will be wrong for file2.php, so file3.php cannot be included.

For include its possible to set some folders where PHP search automatically. When you include a file with a relative path you search in all of that folders. Its better to define the real path to prevent some errors in loading wrong files.

https://secure.php.net/manual/en/function.set-include-path.php

Then you can be sure that you load the correct file.

标签
易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!