include header.php?

Question

PHP

Hello.
You need to include header.php in include_test.php file.
Header.php is on the server. I write like this:

include 'http://www.site.com/wp-content/themes/template/header.php';

and get 500 error - Server Error. And even if I move header.php to the root, I get a 500 error. When I created a simple hello.php file with hello, world, the include went fine.
Where am I doing wrong?
Thanks in advance.

Answer 1

www.php.su/include
namely:
In order for remote inclusion of files to be available, it is necessary to set allow_url_fopen=1 in the configuration file (php.ini).

Answer 2

The path must be full, relative to the server.

Answer 3

Use __DIR__