On Sun, Sep 22, 2019 at 03:46:19PM -0700, Matt Cover wrote: > Unless of course we can simply state via > documentation that any negative return > for which a define doesn't exist is > undefined behavior. In which case, > there is no old vs new behavior and > no need for an ioctl. Simply the > understanding provided by the > documentation. Unfortunately this isn't sufficient: software can easily return a wrong value by mistake, and become dependent on an undefined behaviour. -- MST