For example, I always see autoloaders called like this:
require_once __DIR__ . '/../vendor/autoload.php';
What is the difference between that and the more concise
require_once '../vendor/autoload.php';
?
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.