There is a number of forum variables available on every forum page. These variables are used for the page generation. To use them one has to include the FORUM_ROOT.'include/common.php' file first.
This variable correlates an associative array with some information about a user (user id, group id, username, profile options, user permissions, etc.) For example:
$forum_user['id']contains user's id;
$forum_user['language']contains the language selected in user's profile;
$forum_user['g_post_topics']shows whether the user can post topics or not.
This variable correlates an associative array with all configuration options (board title, sef scheme, etc.) For example:
$forum_config['o_default_lang']contains the default language of the forum;
$forum_config['o_avatars_dir']is the path to the directory, where avatars are saved.
This variable is an instance of the database layer. It is used to perform SQL queries. See the database helper description for details.