Call to undefined function issue

Question

I know there are other, maybe better ways to do what I want to achieve, but I have to use this solution.

Alright, I have two stylesheet files: style.css - normal stylesheet

style-dynamic.php - dynamic stylesheet linked to the first one

I'm using some PHP code in the second one, like:

#body {
    background-color: <?php echo get_option('theme_background');>;                                             
}

Now the point is style.php file doesn't "know" WP functions, and the code above gives:

Fatal error: Call to undefined function get_option() in C:\xampp\htdocs\wordpress\wp-content\themes\mytheme\style-dynamic.php on line 12

I guess I have to load wp_load.php (only?) and that's tricky, because I'm not sure how exactly? I was trying require once, but I'm not sure I'll be able to jump from theme directory right to the WP main dir where wp-load.php file is?

[edit]

Of course

require_once( ABSPATH . 'wp-load.php');

Outputs another error:

Use of undefined constant ABSPATH - assumed 'ABSPATH'

Answer 1

Hopefully better late than never; in case the solution above (by Wordpressor) is not working, you can load wp-load.php like this:

// allow us to use core wordpress functions
    $oldURL = dirname(__FILE__);
    $newURL = str_replace(DIRECTORY_SEPARATOR . 'wp-content' . DIRECTORY_SEPARATOR . 'themes' . DIRECTORY_SEPARATOR . 'THEME_NAME' . DIRECTORY_SEPARATOR . 'assets', '', $oldURL);
    include($newURL . DIRECTORY_SEPARATOR . 'wp-load.php');

Make sure to replace THEME_NAME with your theme's name.

Answer 2

Christ, once again I was fighting with something for a few days straight and found a solution 20 minutes after asking on StackExchange. WHY?

require_once('../../../wp-load.php');