On 6 November 2017 at 17:41, Paolo Bonzini <pbonz...@redhat.com> wrote: > What about > > #define type_max(t) \ > ((t) -1 > 0 \ > ? (t)~0 \ > : (((t)1) << \ > (sizeof(t) * 8 - 1)) - 1) \ > > #define TIME_MAX type_max(time_t) > > ? We don't need it to be a cpp constant, do we? Or if we did, we could > assume it to be signed, it's enough for the three users.
GCC doesn't like this phrasing, it complains qmp.c: In function ‘qmp_expire_password’: qmp.c:334:89: error: integer overflow in expression [-Werror=overflow] because of the shift into the sign bit. Instead we can borrow the TYPE_MAXIMUM macro from gnulib, which uses basically the same approach but avoids the UB and the compiler warning. I'll send a patch in a bit. thanks -- PMM
