not get the warning about the sign change on the return values with using -Wall -Wextra only.
Well, its perfectly legal C to assign `int` to `uint`, and there are old time system interfaces that use `int` where they only return positive values and actually should have used `uint`, so the warning is spurious (and unfixable) in some cases. Thats why it is not included in `-Wall` and `-Wextra`.
The less used warnings tend to be ones that can cause more unsuppressable spurious results, or just plain stupid results (see a recent discussion between @b4n and I about returning small structs from functions that was triggered by one of his warnings :wink: ). Thats why @b4n doesn't advise his option set and use it on Travis, the results cannot be taken at face value, they need interpretation.