Thread

Re: Don't cast away const where possible

Bertrand Drouvot <bertranddrouvot.pg@gmail.com> — 2025-12-29T09:01:46Z

Hi,

On Mon, Dec 22, 2025 at 12:53:03PM +0100, Peter Eisentraut wrote:
> On 18.12.25 14:55, Bertrand Drouvot wrote:
> > Some functions are casting away the const qualifiers from their signatures in
> > local variables.
> 
> @@ -1304,8 +1304,8 @@ merge_overlapping_ranges(FmgrInfo *cmp, Oid colloid,
>  static int
>  compare_distances(const void *a, const void *b)
>  {
> -       DistanceValue *da = (DistanceValue *) a;
> -       DistanceValue *db = (DistanceValue *) b;
> +       const DistanceValue *da = (const DistanceValue *) a;
> +       const DistanceValue *db = (const DistanceValue *) b;
> 
> I wonder if the better fix here wouldn't be to get rid of the cast. It's not
> necessary, and without it the compiler would automatically warn about
> qualifier mismatches.

Yeah, that looks better as it provides an extra safety check should the function
signature change.

> These comparison functions seem to be a common
> pattern.

Right, in the attached I applied your proposal on all those places.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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