> On Nov 14, 2025, at 09:36, Qing Zhao <[email protected]> wrote:
>
>
>
>> On Nov 14, 2025, at 01:50, Martin Uecker <[email protected]> wrote:
>>
>> Am Donnerstag, dem 13.11.2025 um 20:41 +0000 schrieb Qing Zhao:
>>>
>>>> On Nov 13, 2025, at 14:17, Martin Uecker <[email protected]> wrote:
>>>>
>>>> Am Donnerstag, dem 13.11.2025 um 15:44 +0000 schrieb Qing Zhao:
>>>>
>>>>>
>>>
>>
>>
>>>>
>>>>>
>>>>>>
>>>>>> You would then check correctness of the attribute only when the parent
>>>>>> type is complete.
>>>>>
>>>>> Okay.
>>>>>>
>>>>>> If we want to support counted_by in even more generic cases,
>>>>>
>>>>> What kind of more generic cases? Any example?
>>>>
>>>> I was thinking about
>>>>
>>>> struct bar {
>>>> char *buf __counted_by(n);
>>>> };
>>>>
>>>> struct foo {
>>>> int n;
>>>> struct bar;
>>>> };
>>>>
>>>> which is allowed with -fms-extensions.
>>>>
>>>> I don't think we should support this.
>>>
>>> Don’t support this even when -fms-extensions is enabled?
>>
>> Yes, because then you can't emit an error for
>> struct bar anymore (e.g. as the in the following example),
>> because we can't know whether it might be used later
>> as an anonymous field where it could refer to some other 'n'.
>>
>> struct bar {
>> int m;
>> char *buf __counted_by(n);
>> };
>>
>> But I think an error would be useful here.
>
> Okay, make sense to me.
> I will add this.
At the same time, shall we support the following with -fms-extensions:
/* -fms-extensions */
struct ids
{
int length_ad;
int length_na;
};
struct person
{
int age;
int weight;
struct ids; // Anonymous structure, no name needed
char *address __attribute__ ((counted_by (length_ad)));
char name[] __attribute__ ((counted_by (length_na)));
} *Jim;
i.e, in the above, the counted_by fields for Pointer “address” and FAM “name”
are in the anonymous
structure “struct ids” which is not inlined into the “struct person”.
Any idea on this?
Qing
>
> Thanks a lot.
>
> Qing
>>
>>
>> Martin
