https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116016
--- Comment #31 from Kees Cook <kees at outflux dot net> ---
(In reply to Qing Zhao from comment #25)
> The source code need to be:
>
> If (__builtin_get_counted_by (P->FAM))
> __builtin_get_counted_by (P->FAM) = COUNT;
>
> Yes, I agree that this is good too for the original purpose. And also even
> simpler and more flexible.
> Kees might have more comments here. (Not sure any other impact on handling
> the original problem he had with the new __builtin_get_counted_by).
Yeah, I like this. It gives much more obvious semantics instead of hiding a
no-op, and this could be used for _reading_ as well as writing the value. This
means we could also write, for example, loop constructs with only the FAM:
typeof(*__builtin_get_counted_by(P->FAM)) idx;
for (idx = 0; idx < *__builtin_get_counted_by(P->FAM); idx++)
do_things(P->FAM[idx]);
