Function IODataQueueDataAvailable 

pub unsafe extern "C-unwind" fn IODataQueueDataAvailable(
    data_queue: *mut IODataQueueMemory,
) -> bool

Used to determine if more data is available on the queue.

Parameter dataQueue: The IODataQueueMemory region mapped from the kernel.

Returns: Returns true if data is available and false if not.

Safety

data_queue must be a valid pointer.