Re: new gcc 7.0.1 warnings

2017-02-18 18:35 GMT+01:00 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:

> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> > float.c:382:5: note: ‘snprintf’ output between 2 and 311 bytes into a
> > destination of size 65
> > float.c:618:5: note: ‘snprintf’ output between 2 and 311 bytes into a
> > destination of size 129
>
> That's kind of annoying. I suppose the point is that the compiler can't
> see what precision we're selecting, and with sufficiently large precision
> the output could be that wide. But actually the precision should be small
> enough to make that OK.
>
> Do the warnings go away if you add some explicit guard to the precision
> variable, say like this:
>
> {
> int ndig = DBL_DIG + extra_float_digits;
>
> if (ndig < 1)
> ndig = 1;
> + if (ndig > 50)
> + ndig = 50;
>

This fix doesn't help

Regards

Pavel

>
> snprintf(ascii, MAXDOUBLEWIDTH + 1, "%.*g", ndig, num);
> }
>
> If not, I guess we could increase the size of the palloc'd strings,
> but that seems wasteful.
>
> regards, tom lane
>