Hi @fle, thanks for getting in touch. Judging by the function name, you are using the Tobii Pro SDK?
In this case, please reach out the Tobii Pro Support team who specialise in this product and can provide you an answer directly.
Please raise a ticket with them @ http://www.tobiipro.com/contact/contact-support/
Apologies for the inconvenience and thanks for your understanding. Best Wishes.