"format not a string literal"

[Eli Zaretskii]

>  >   printf (n == 1 ? "%d file" : "%d files", n);
> 
> An easy to fix bad behavior is not a reason to change the warning,
> even if lots of people do it.  This is especially true if the warning
> points exactly to the place where the problem occurs and the fix is
> immediately clear.
> 
> Note I submitted patches to fix the cases in gcc which did the above
> ?: silliness as well as several array format string usages.  The
> warning in those cases is entirely legitimate.

Could you please explain why this practice is ``silly'', and why does
it deserve a warning?  As someone who uses such code, perhaps out of
utter ignorance, I'd like to know why I will be punished by the new
versions of GCC.

In particular, it would be nice to know whether such code violates
some established standards, and if so, which ones.

Thanks.