On Wed, Jul 19, 2023 at 10:27 AM Adhemerval Zanella Netto <
adhemerval.zanella@linaro.org> wrote:

>
>
> On 19/07/23 09:40, Cristian Rodríguez via Libc-alpha wrote:
> > On Mon, Jul 10, 2023 at 11:05 AM Cristian Rodríguez <
> cristian@rodriguez.im>
> > wrote:
> >
> >> Currently GCC 13  -fstrict-flex-arrays cannot be used safely with user
> >> code because the library makes use of pre-c99 flexible arrays.
> >>
> >> This series introduces a macro to annotate such uses and grandfathers-in
> >> this legacy use.
> >>
> >> This series only cover the user-visible *library* types. the linux
> kernel
> >> types
> >> are subject to a different patch set and discussion since the kernel has
> >> moved on to c11 leaving pre-c99 compatibilty behind.
> >>
> >>
> >>
> >>
> > Any comments about this series.. ? as is it should introduce no
> > regressions.
>
>
> Can't we use the already define __flexarr/__glibc_c99_flexarr_available
> macro
> instead?


If I did only that, sizeof public structures may change causing an abi
break.
if breaking the ABi is an option then one can switch completely to c99
flexible arrays and using/importing DECL_FLEX_ARRAY macro from the linux
kernel and move on.

I concluded it was better to grandfather them in and leave them as special
cases is the less painful solution for user visible parts, internals can
just  use standard flex arrays.