From: Thomas Gleixner > Sent: 20 October 2019 20:53 > On Sun, 20 Oct 2019, Andreas Schwab wrote: > > On Okt 20 2019, Thomas Gleixner wrote: > > > > > POSIX does not mention anything about the validity of the pointer handed > > > to > > > clock_getres(). > > > > Sure it does: "If the argument res is not NULL, the resolution of the > > specified clock shall be stored in the location pointed to by res. If > > res is NULL, the clock resolution is not returned.". > > Sigh, that makes a lot of sense - NOT. > > But for the sake of making a non-sensical specification happy we can add a > NULL pointer check for this. The interesting question is what should be > returned in this case. The kernel returns EFAULT which is probably not > POSIX compliant either.
The application won't see errno == EFAULT. EFAULT gets converted to SIGSEGV (probably) in the return-to-user code path. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)