bug#32189: 27.0.50; GCC 7 warning due to -Wformat-truncation=2

[Ken Brown <kbrown@cornell.edu>]

On 7/19/2018 2:10 AM, Philipp Stephani wrote:
> Ken Brown <kbrown@cornell.edu <mailto:kbrown@cornell.edu>> schrieb am 
> Mi., 18. Juli 2018 um 21:44 Uhr:

>     $ cat test.c
>     #include <stdio.h>
>     int
>     main ()
>     {
>         char buffer[16];
>         short a;
>         snprintf (buffer, 16, "%3.1f", a);
>     }
> 
> 
> This is undefined behavior, as %f requires a double argument.

Then cast the argument to double; this doesn't change the warning, which 
claims that the output could be 312 bytes.

Ken