Re: Avoid undefined behavior with msvc compiler (src/include/port/pg_bitutils.h)

On Mon, Jul 31, 2023 at 5:57 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> John Naylor <john.naylor@enterprisedb.com> writes:

> > Works for me, so done that way for both forward and reverse variants.
Since
> > the return value is no longer checked in any builds, I thought about
> > removing the variable containing it, but it seems best to leave it
behind
> > for clarity since these are not our functions.
>
> Hmm, aren't you risking "variable is set but not used" warnings?
> Personally I'd have made these like
>
>     (void) _BitScanReverse(&result, word);

I'd reasoned that such a warning would have showed up in non-assert builds
already, but I neglected to consider that those could have different
warning settings. For the time being drongo shows green, at least, but
we'll see.

--
John Naylor
EDB: http://www.enterprisedb.com