wordpress plugin require_once file – can’t user wordpress functions

Question

I’m not sure if you’re trying to use WordPress functions outside of the actual WordPress application, but to accomplish this you simply need to do:

require( 'path-to-wordpress/wp-load.php' );

at the top of your file, if the path to the WordPress application is in fact $_SERVER['DOCUMENT_ROOT'] then you would do

require ( $_SERVER['DOCUMENT_ROOT'] . '/wp-load.php' );