Em seg., 31 de ago. de 2020 às 16:39, Peter Geoghegan <p...@bowt.ie> escreveu:
> On Mon, Aug 31, 2020 at 11:42 AM Andres Freund <and...@anarazel.de> wrote: > > Unsigned integer overflow is well defined in the standard. So I don't > understand what this is purporting to warn about. > > Presumably it's simply warning that the value -4294901760 (i.e. the > result of 3 - 4294901763) cannot be faithfully represented as an > unsigned int. This is true, of course. It's just not relevant. > > I'm pretty sure that UBSan does not actually state that this is > undefined behavior. At least Ranier's sample output didn't seem to > indicate it. > 4294901763 can not store at unsigned int (TransactionID is uint32_t). TransactionId id2 at TransactionIdPrecedes already has an overflow, before anything is done. Ranier Vilela
