Write To Log From Php Code

Hi community!
I run CS-Cart in the "Multivendor Plus" variant.
I can (successfully) create a vendor via the API. Nevertheless I would like to write some log entries (e.g. to the log which is offered under > Administration > Log).
How to do this from PHP code?
Any help is appreciated.
Best regards

You should use the fn_log_event function (app/functions/fn.log.php)