Why can't I connect autoload.php?

Question

PHP

Mistake

Fatal error: require_once(): Failed opening required 'root/vendor/autoload.php' (include_path='.:') in........

In code

<?
require_once($_SERVER['DOCUMENT_ROOT'] . "/bitrix/modules/main/include/prolog_before.php");
require_once 'root/vendor/autoload.php';
?>

Composer installed globally

Answer 1

Learning the difference between absolute and relative paths
In this case, it is advisable not to enter the path hard, but to build from the current file using the built-in constant __DIR__