Question

File tree;

• boot.php
• panel/index.php
• panel/inc/start.php
• panel/inc/functions.php

Process:

• index.php; requires ‘inc/start.php’
• start.php; requires ‘../boot.php’ and ‘functions.php’
• (require_once ‘x.php’ used)

Everything works when index.php called. Why i don’t have to use ../../boot.php instead of ../boot.php?
If relative folder is /panel, then require ‘functions.php’ should fail. If it is /panel/inc, require ‘../boot.php’ should fail. But eveything works. How?

Note: I know i should use absolute folder to include files. I am just trying to understand how this example works.

Answer 1

As for the PHP manual:

http://php.net/manual/en/function.require-once.php

http://www.php.net/manual/en/function.include.php

If a path is defined — whether absolute (starting with a drive letter
or \ on Windows, or / on Unix/Linux systems) or relative to the
current directory (starting with . or ..)

When PHP includes / requires a file, it looks for a path relative to the current file position.