How do you use SetEnv to read variables in Apache?

I want to set an env variable that has the DOC_ROOT info but nothing

SetEnv PROJECT_BASE %{ENV:DOC_ROOT}
SetEnv LAYOUT_HOME  %{ENV:PROJECT_BASE}"/html/app/wordpress/"

and then be able to access LAYOUT_HOME in php

Ho开发者_StackOverfloww can I do this?

Variables are accesible via :

$_SERVER["LAYOUT_HOME"] and $_SERVER["PROJECT_BASE"] global variable.

A simple test if to execute the next command in php

<?php phpinfo(); ?>

and check if the variable is present and is defined.

If not, then may be exist some restricting in the php installation ( for example in a share ambiance - sharedhosting)

So far it's not possible. All you can do is to set request headers with RequestHeader. So you'll have you variable in environ but with "HTTP_" prefix.