Hi Rysc,
thanks so much for your answer: I ended using your solution just few minutes before reading your post: I was trying almost everything to make my fifo work, so I tried to "split" the if..then and now it's working (I had the same problem on the fifowrite, now solved). Anyway, I must admit that mine were just tryouts, your solution with an explanation is surely better!
thanks again, all the best, C.
PS point 1) of my first post - the warning - is still there.. until it seems to work I don't care of it, but I'm curious why I have this warning!