BSD Library nrf_connect() results an EINPROGRESS error when non blocking is enabled


Is it expected to get an EINPROGRESS error when calling nrf_connect() with NRF_O_NONBLOCK set. How do I know if the call was successful or not? Should I expect a positive result from nrf_poll()?

By the way our firmware is running on a custom OS and preferred non blocking calls in this current situation. 

Thank you.