On Thu, Feb 14, 2019 at 11:08:26AM +0000, Jonathan Wakely wrote: > On Thu, 14 Feb 2019 at 10:52, Kalamatee <kalamatee@xxxxxxxxx> wrote: > > > > it is used by acpica to implement snprintf and sprint -: > > > > https://github.com/acpica/acpica/blob/master/source/components/utilities/utprint.c > > > > see line 837. > > > > Clearly Format and Args aren't known at compile time, however the invocation is correct and valid so I don't get why the incorrect warning is shown. > > > > (I could understand a message similar to other -format ones that suggest the operation may overflow the buffer - but that's not what the diagnostic says, it implies the second parameter cant be over INT_MAX). > > It doesn't say it can't be over INT_MAX, it just warns you that it is > over INT_MAX (because that means no checking on the output length). That does mean it does not belong in -Wformat-truncation=1 (which is what we have here). It does not belong in -Wall. It will warn for all valid code that uses this language feature! And it isn't necessarily a questionable feature. Also, the documentation for =1 says this warns for "calls [...] that will most likely result in output truncation", which isn't true here, one hopes. Segher
