[cfe-commits] [Patch] Warn about non-standard format strings (PR12017)

[Hans Wennborg]

On Mon, Feb 20, 2012 at 21:00, Ted Kremenek <kremenek at apple.com> wrote:
> On Feb 20, 2012, at 12:21 PM, Joerg Sonnenberger <joerg at britannica.bec.de>
> wrote:
>
> There's "non-standard" and then there's completely unportable.  Warnings
> like:
>
> +  // Combining 'L' with an integer conversion specifier.
> +  printf("%Li", (long long)42); // expected-warning{{using the length
> modifier 'L' with the conversion specifier 'i' is non-standard}}
> +  printf("%Lo", (long long)42); // expected-warning{{using the length
> modifier 'L' with the conversion specifier 'o' is non-standard}}
>

[...]

> Do we really silently accept them?  Until very recently (a month ago?), we
> emitted:
>
> t.c:4:12: warning: length modifier 'L' results in undefined behavior or no
>       effect with 'i' conversion specifier [-Wformat]
>   printf("%Li", (long long) 2);
>           ~^~
> 1 warning generated.
>
>
> Now I see that TOT doesn't warn here.  Is this accepted somewhere?  I see no
> test cases in clang/test that shows we should accept this.  Was this an
> intentional change, or a regression?

r148859 made them accepted about a month ago. Looks intentional to me :)