|wp-includes/capabilities.php: current_user_can()|| |
Returns whether the current user has the specified capability.
|wp-includes/pluggable.php: is_user_logged_in()|| |
Determines whether the current visitor is a logged in user.
|wp-includes/load.php: is_admin()|| |
Determines whether the current request is for an administrative interface page.
|wp-includes/plugin.php: has_filter()|| |
Check if any filter has been registered for a hook.